Harbor Diversified (HRBR) 10-K 1 Apr 21 2020 FY Annual report Financial data

Cover

Cover - USD ($)	12 Months Ended
	Dec. 31, 2020	Mar. 26, 2021	Jun. 30, 2020
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Registrant Name	HARBOR DIVERSIFIED, INC.
Entity Central Index Key	0000899394
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Interactive Data Current	Yes
Entity Small Business	true
Entity Shell Company	false
Entity Emerging Growth Company	false
Entity File Number	001-34584
Entity Incorporation State Country Code	DE
Entity Tax Identification Number	13-3697002
Entity Address Address Line1	W6390 Challenger Drive
Entity Address Address Line2	Suite 203
Entity Address City Or Town	Appleton
Entity Address Postal Zip Code	54914-9120
Entity Address State Or Province	WI
City Area Code	920
Local Phone Number	749-4188
Entity Common Stock, Shares Outstanding		54,863,305
Entity Public Float			$ 1,743,000
ICFR Auditor Attestation Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current Assets
Cash and cash equivalents	$ 130,373	$ 69,454
Restricted cash	820	819
Accounts receivable, less allowance of $59 as of December 31, 2020 and $129 as of December 31, 2019	7,977	5,525
Spare parts and supplies, less allowances of $9,649 as of December 31, 2020 and $8,389 as of December 31, 2019	5,937	7,819
Contract costs	433	400
Prepaid expenses and other	2,310	1,003
Total Current Assets	147,850	85,020
Property and Equipment
Flight property and equipment	258,981	242,613
Ground property and equipment	8,127	8,305
Less accumulated depreciation	(117,717)	(99,680)
Net Property and Equipment	149,391	151,238
Other Assets
Operating lease right of use asset	8,582	24,026
Intangibles	5,300	5,300
Long-term investments	4,275	4,275
Long-term contract costs	566	867
Long-term note receivable	32,440
Other	2,049	1,906
Total Other Assets	53,212	36,374
Total Assets	350,453	272,632
Current Liabilities
Accounts payable	11,773	16,608
Accrued payroll and employee benefits	14,761	15,474
Current portion of operating lease liability	1,361	6,311
Other accrued expenses	345	327
Contract liabilities	18,443	8,342
Income taxes payable	107	213
Current portion of long-term debt (stated principal amount of $20,922 as of December 31, 2020 and $7,198 as of December 31, 2019)	23,652	12,845
Total Current Liabilities	70,442	60,120
Other Liabilities
Long-term debt (stated principal amount of $86,066 as of December 31, 2020 and $96,988 as of December 31, 2019)	94,186	107,838
Long-term promissory note	4,275	4,275
Deferred tax liability	6,200	2,599
Long-term operating lease liability	4,351	10,538
Long-term contract liabilities	7,780	8,086
Deferred revenue, net of current portion	30,720
Other	2,774	1,655
Total Long-Term Liabilities	150,286	134,991
Commitments and Contingencies (Note 8)
Mezzanine Equity Series C Convertible Redeemable Preferred Stock, $0.01 par value, 4,000,000 shares authorized, issued and outstanding at December 31, 2020 and none at December 31, 2019	13,200
Stockholders' Equity
Common Stock, $0.01 par value, 100,000,000 shares authorized, 55,481,140 shares issued and 54,863,305 shares outstanding at December 31, 2020 and December 31, 2019	555	555
Additional paid-in capital	288,221	288,980
Retained deficit	(171,770)	(211,533)
Treasury stock	(481)	(481)
Total Stockholders' Equity	116,525	77,521
Total Liabilities and Stockholders' Equity	$ 350,453	$ 272,632

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Allowance for doubtful accounts receivables	$ 59	$ 129
Inventory allowances valuation reserves	9,649	8,389
Current portion of long-term debt principal amount	20,922	7,198
Non-current portion of long term debt principal amount	$ 86,066	$ 96,988
Common stock par value	$ 0.01	$ 0.01
Common stock share authorized	100,000,000	100,000,000
Common stock share issued	55,481,140	55,481,140
Common stock share outstanding	54,863,305	54,863,305
Series C Redeemable Convertible Preferred Stock [Member]
Temporary equity par value	$ 0.01	$ 0.01
Temporary equity shares authorized	4,000,000	0
Temporary equity shares issued	4,000,000	0
Temporary equity shares outstanding	4,000,000	0

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating Revenues
Total Operating Revenues	$ 185,949	$ 263,605
Operating Expenses
Payroll and related costs	99,100	126,505
Aircraft fuel and oil	55	172
Aircraft maintenance, materials and repairs	27,350	57,827
Aircraft rent	6,713	43,118
Other rents	4,580	8,372
Depreciation, amortization and obsolescence	27,222	25,238
CARES Act Payroll Support Program	(42,185)
Purchased services and other	19,764	23,235
Total Operating Expenses	142,599	284,467
Income (Loss) From Operations	43,350	(20,862)
Other Income (Expense)
Interest income	628	1,271
Interest expense	(1,736)	(1,806)
Other	(19)	2,505
Total Other Income (Expense)	(1,127)	1,970
Net Income (Loss) Before Taxes	42,223	(18,892)
Income Tax Expense	2,460	322
Net Income (Loss)	39,763	(19,214)
Preferred Stock Dividends	759
Net Income (Loss) available to Common Stockholders	$ 39,004	$ (19,214)
Basic earnings (loss) per share	$ 0.71	$ (0.35)
Diluted earnings (loss) per share	$ 0.56	$ (0.35)
Weighted average common shares:
Basic	54,863	54,863
Diluted	71,199	54,863
Contract Revenue [Member]
Operating Revenues
Total Operating Revenues	$ 185,866	$ 263,495
Contract Service and Other [Member]
Operating Revenues
Total Operating Revenues	$ 83	$ 110

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Mezzanine Equity Series C Convertible Redeemable Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Repurchased Stock [Member]
Beginning Balance at Dec. 31, 2018	$ 96,735		$ 555	$ 288,980	$ (192,319)	$ (481)
Beginning balance, Shares at Dec. 31, 2018			54,863			618
Net income (loss)	(19,214)				(19,214)
Ending Balance at Dec. 31, 2019	77,521		$ 555	288,980	(211,533)	$ (481)
Ending balance, shares at Dec. 31, 2019			54,863			618
Net income (loss)	39,763				39,763
Dividend	(759)			(759)
Preferred Stock		$ 13,200
Preferred Stock, Shares		4,000
Ending Balance at Dec. 31, 2020	$ 116,525	$ 13,200	$ 555	$ 288,221	$ (171,770)	$ (481)
Ending balance, shares at Dec. 31, 2020		4,000	54,863			618

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Cash Flows From Operating Activities
Net income (loss)	$ 39,763	$ (19,214)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, amortization and obsolescence allowance	27,222	25,238
Aircraft lease termination costs	1,263	19,353
Amortization of contract costs	(2,502)	(3,725)
Amortization of engine overhauls	1,265	4,067
Deferred income taxes	3,601	744
Loss on disposition of property	648	2,528
Changes in operating assets and liabilities:
Accounts receivable	(2,444)	3,989
Notes Receivable	(32,440)	0
Spare parts and supplies	622	(402)
Prepaid expenses and other	(1,885)	2,466
Operating lease right of use asset	2,520	(1,987)
Accounts payable	(7,790)	(7,706)
Accrued payroll and employee benefits	(713)	(372)
Other accrued expenses	18	(996)
Long-term deferred revenue	30,720	0
Contract liabilities	12,297	1,417
Income taxes payable	(106)	(100)
Other long-term liabilities	1,119	246
Net Cash Provided by Operating Activities	73,178	25,546
Cash Flows From Investing Activities
Additions to property and equipment	(8,749)	(21,498)
Proceeds on disposition of property and equipment	95	562
Net Cash Used in Investing Activities	(8,654)	(20,936)
Cash Flows From Financing Activities
Repayments of long-term debt	(12,845)	(7,198)
Proceeds from note payable	10,000	11,790
Dividends paid	(759)	0
Net Cash (Used in) Provided by Financing Activities	(3,604)	4,592
Increase in Cash, Cash Equivalents and Restricted Cash	60,920	9,202
Cash, Cash Equivalents and Restricted Cash, beginning of year	70,273	61,071
Cash, Cash Equivalents and Restricted Cash, end of year	$ 131,193	$ 70,273

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	1. Summary of Significant Accounting Policies Basis of Presentation The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (GAAP) and include the accounts of Harbor Diversified, Inc. and subsidiaries (collectively, the Company). Harbor Diversified, Inc. is a non-operating holding company is a non-operating entity with Description of Operations The Company has principal lines of business focused on (1) providing air transportation through Air Wisconsin (airline business), (2) acquiring flight equipment for the purpose of leasing the equipment to Air Wisconsin and (3) providing flight equipment financing to Air Wisconsin. The airline business is operated entirely through Air Wisconsin, which is an independent regional air carrier that is engaged in the business of providing scheduled passenger service under a capacity purchase agreement (the United capacity purchase agreement) with United Airlines, Inc. (United) that was entered into in February 2017 and amended in October 2020. For additional information, refer to Note 3, Capacity Purchase Agreement with United. Air Wisconsin operates as a United Express carrier with a significant presence at both Chicago O’Hare and Washington-Dulles, two of United’s key domestic hubs. Segment Reporting Operating segments are defined as components of an enterprise about which separate financial information is available that is evaluated regularly by the chief operating decision maker in deciding how to allocate resources and in assessing operating performance. In consideration of Accounting Standards Codification (ASC) 280, “ Segment Reporting As further discussed below, substantially all of our operating revenue in 2020 and 2019 was derived from operations associated with United. Contract and Other Revenues The Company recognizes revenue under the United capacity purchase agreement over time as services are provided. United pays the Company a fixed rate for each departure and block hour (measured from takeoff to landing, including taxi time), and a fixed amount per aircraft per day, with additional incentives primarily based on flight completion, on-time The United capacity purchase agreement includes weekly provisional cash payments based on a projected level of flying each month. The Company and United subsequently reconcile these payments to the actual completed flight activity on a monthly basis. Under the United capacity purchase agreement, the Company is eligible to receive incentive compensation upon the achievement of certain performance criteria (provided that, pursuant to the amendment to the United capacity purchase agreement, no incentive or penalty payments were made for the period from April 1, 2020 through September 30, 2020). The incentives are defined in the agreement and are determined and measured on a monthly basis. At the end of each month during the term of the agreement, the Company calculates the incentives achieved during that period and recognizes revenue accordingly, subject to the variable constraint guidance under Financial Accounting Standards Board (FASB) Accounting Standards Update (ASU) No. 2014-09, Revenue from Contracts with Customers As discussed above, under the United capacity purchase agreement, Air Wisconsin is paid a fixed amount per aircraft per day for each month during the term of the agreement. In accordance with GAAP, the Company recognizes revenue related to the fixed payments on a proportional basis taking into account the number of flights actually completed in that period relative to the number of flights expected to be completed in subsequent periods during the remaining term of the agreement. Due to the material decrease in completed flights for the year ended December 31, 2020 from historical levels and anticipated future levels in periods within the remaining contract term, Air Wisconsin determined that the amount of the fixed payments it received was disproportionately high relative to anticipated fixed revenue for future periods due to fewer flights completed in the year ended December 31, 2020. Air Wisconsin non-refundable The amount of revenue recognized for the year ended December 31, 2020 that was previously recorded as a contract liability is $7,116. In October 2020, Air Wisconsin entered into an amendment to the United capacity purchase agreement (CPA amendment), which, among other things, provided for the payment or accrual of certain amounts by United to Air Wisconsin based on certain scheduling benchmarks. In conjunction with the significant reduction in departures and block hours caused by the COVID-19 pandemic, and as a result of the CPA amendment, management determined, using a significant amount of judgement, that from an accounting perspective, a new performance obligation was created by United requiring Air Wisconsin to stand ready to deliver flight services. Air Wisconsin determined, using the expected cost plus a margin method, that the United stand ready rate represents the relative stand-alone selling price of the performance obligation. The stand ready performance obligation will be recognized over time on a straight line basis based on the number of unscheduled block hours below a minimum threshold at the stand ready rate as determined by the CPA amendment. For the year ending December 31, 2020, Air Wisconsin recorded $21,392 in revenue related to this performance obligation. This amount was recorded in tong-term notes receivable on the balance sheet as of December 31, 2020. As part of the CPA amendment, Air Wisconsin also settled outstanding issues, including the opening and closing of maintenance bases. United agreed to accrue a liability to Air Wisconsin in the amount of $11,048 along with a cash settlement of $670. These amounts were recognized using a cumulative catchup adjustment based on prior and future expected departures. In total, Air Wisconsin recognized revenue of $7,307 and deferred the remaining portion which will be recognized in proportion to future departures. These accrued amounts contain a significant financing component and any interest income is separately reported in the statement of operations. Further, the accrued amounts are evidenced by notes receivable payable by United to Air Wisconsin. As of December 31, 2020, these notes totaled 2020, interest receivable on these notes totaled $309. United makes provisional cash payments to the Company during each month of service based on monthly flight schedules. These provisional cash payments are reconciled based on actual completed flights after each month’s flight activity is completed. As of December 31, 2020, United owed Air Wisconsin $1,180 which is recorded in “Accounts receivable less allowances” on the balance sheet. Other revenues are immaterial and primarily consist of the sales of parts to other airlines. The transaction price for the sale of these parts generally is fair market value. Cash and Cash Equivalents Investments and deposits with a maturity of three months or less when acquired and money market funds are considered cash and cash equivalents. Restricted Cash Restricted cash represents amounts escrowed in an interest-bearing account relating to the Company’s letters of credit. Spare Parts and Supplies Expendable parts are stated at average cost less an obsolescence allowance. The Company provides for an allowance for obsolescence after considering the useful life of the aircraft fleet, the estimated cost of expendable parts expected to be on hand at the end of the useful life and the estimated salvage value of the parts. This allowance is based on management estimates and is subject to change. Expendable parts are charged to expense when used. Expendable parts that are repairable are returned to inventory at the average cost of comparable parts, less a reserve for scrap. Supplies are stated at average cost. Property and Equipment and Depreciation Property and equipment are stated at cost and depreciated over their useful lives to their estimated residual values using the straight-line method as follows: Assets Depreciable Life Current Residual Value Aircraft 7 years $ 50,000 Rotable parts 7 years 10 % Spare engines 7 years $ 25,000 Ground equipment up to 10 years 0 % Office equipment up to 10 years 0 % Leasehold improvements Shorter of asset or lease life 0 % Air Wisconsin’s capitalized engine maintenance costs are amortized over their estimated useful life measured in remaining engine cycles to the next scheduled shop event. Lotus’ engine maintenance costs are expensed. Depreciation expense in 2020 and 2019 was $25,719 and $23,578, respectively, and is included in depreciation, amortization, and obsolescence in the accompanying consolidated statements of operations. Impairment of Long-Lived Assets The Company evaluates long-lived assets for potential impairment and records impairment losses on long-lived assets when events and circumstances indicate the assets might be impaired and the undiscounted cash flows estimated to be generated by those assets are less than their carrying amounts. Impairment losses are measured by comparing the fair value of the assets to their carrying amounts. In determining the need to record impairment charges, the Company is required to make certain estimates and assumptions regarding such things as the current fair market value of the assets and future net cash flows to be generated by the assets. If there are subsequent changes to these estimates or assumptions, or if actual results differ from these estimates or assumptions, such changes could impact the financial statements in the future. The Company conducted a qualitative impairment assessment of its long-lived assets and determined that no quantitative impairment tests were needed as of December 31, 2020. Impairment of Intangible Assets Indefinite-lived intangible assets are not subject to amortization but are subject to an annual assessment for impairment by applying a fair-value-based test. Since Air Wisconsin’s trade names and air carrier certificate have indefinite lives, there is no amortization. The Company evaluated these assets for impairment and determined that no impairment existed as of December 31, 2020 or 2019. Maintenance The Company operates its aircraft under a continuous inspection and maintenance program. The normal cost of recurring maintenance is expensed when incurred except for planned major maintenance activities for engines where the deferral method of accounting is applied. Income Taxes The Company utilizes the asset and liability method for accounting for income taxes. Under the asset and liability method, deferred tax assets and liabilities are determined based upon the estimated future tax effects of differences between the financial statement and tax basis of assets and liabilities, as measured by the current applicable tax rates. Deferred tax expense represents the result of changes in deferred tax assets and liabilities. As required by the uncertain tax position guidance, the Company recognizes the financial statement benefit of a tax position only after determining that the relevant tax authority would more-likely-than-not more-likely-than-not The Company is subject to federal, state and local income taxes in the United States and various states. Tax regulations within each jurisdiction are subject to the interpretation of the related tax laws and regulations and require significant judgment to apply. The Company is no longer subject to U.S. federal income tax examinations for the years prior to 2017. With a few exceptions, the Company is no longer subject to state or local income tax examinations for the years prior to 2016. As of December 31, 2020, the Company had no outstanding tax examinations. The Company recognizes interest and penalties related to unrecognized tax benefits in income tax expense for all periods presented. The Company had accrued $99 and $121 for the payment of interest and penalties at December 31, 2020 and 2019, respectively. Comprehensive Income The Company does not have any components of comprehensive income and, as of December 31, 2020 and 2019, comprehensive income is equal to net income reported in the consolidated statements of operations. Concentration of Credit Risk The Company at times has had bank deposits in excess of the Federal Deposit Insurance Corporation (FDIC) insurance limit. Concentration of Customer Risk Substantially all the Company’s revenues in the years ended December 31, 2020 and 2019 were derived from the United capacity purchase agreement. Refer to Note 3 for additional information. Estimates and Assumptions The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ materially from those estimates. Fair Value of Financial Instruments The Company’s financial instruments include cash and cash equivalents, restricted cash, accounts receivable, notes receivable, long-term investments, accounts payable, and long-term debt. The Company believes the carrying amounts of these financial instruments are a reasonable estimate of their fair value because of the short-term nature of such instruments, or, in the case of long-term debt, because of interest rates available to the Company for similar obligations. Long-term investments are held-to-maturity Fair value is defined as the price that would be received to sell an asset, or paid to transfer a liability, in an orderly transaction between market participants at the measurement date (that is, an exit price). ASC 820 establishes a three-tier fair value hierarchy, which prioritizes inputs used in fair value. The tiers are as follows: Level 1 - Quoted market prices in active markets for identical assets or liabilities. Level 2 - Inputs other than Level 1 inputs that are either directly or indirectly observable. Level 3 - Unobservable inputs developed using the Company’s estimates and assumptions, which reflect those that market participants would use. The determination of where an asset or liability falls in the hierarchy requires significant judgment. The Company evaluates these determinations annually, and it is possible that an asset or liability may be classified differently from year to year. However, the Company expects that changes in classifications between levels will be rare. The Company classifies money market funds and deposits as Level 1 and long-term investments as Recently Adopted Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) (Topic 842). ASU 2016-02 is intended to improve financial reporting of leasing transactions by requiring organizations that lease assets to recognize assets and liabilities for the rights and obligations created by leases on the balance sheet. The accounting update also requires additional disclosures surrounding the amount, timing, and uncertainty of cash flows arising from leases. The Company adopted Topic 842 effective January 1, 2019 and elected the package of transition practical expedients for expired or existing contracts, which does not require reassessment of: (1) whether any of the Company’s contracts are or contain leases, (2) lease classification, and (3) initial direct costs. In July 2018, the FASB issued ASU No. 2018-11, “Targeted Improvements – Leases (Topic 842).” This update provides an optional approach that allows entities to elect to apply the standard using the modified retrospective approach at its effective date, versus recasting the prior years as presented. If this adoption method is elected, an entity would recognize a cumulative-effect adjustment to the opening balance of retained earnings in the year of adoption. The Company elected this adoption method, however, an adjustment was not necessary to opening retained earnings. Additionally, the Company’s adoption of Topic 842 did not have a significant impact on the recognition, measurement or presentation of lease revenue and lease expenses within the financial statements of operations and statement of cash flows. The Company’s prepaid aircraft rents and accrued aircraft rents that were separately stated in the Company’s December 31, 2018 balance sheet have been classified as a component of the Company’s right-of-use assets effective January 1, 2019. As a result of the adoption of the new lease accounting guidance, the Company recognized the following ROU assets and lease liabilities as of January 1, 2019: Right-of-use assets – operating leases $ 70,892 Lease liabilities – operating leases $ 40,921 In August 2018, the FASB issued ASU 2018-13, Fair Value Measurements Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement. 2018-13 Recent Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses Measurement of Credit Losses on Financial Instruments 2016-13). 2016-13 2016-13 2016-13 In August 2020, the FASB issued ASU No. 2020-06, Debt 470-20); Debt with Conversion and Other Options and Derivatives and Hedging 815-40); Contracts in Entity’s Own Equity 2020-06). 2020-06 2020-06 Reclassification In accordance with ASU 2016-18,

Liquidity

Liquidity	12 Months Ended
	Dec. 31, 2020
Text Block [Abstract]
Liquidity and Management's Plan, COVID-19	2. Liquidity The Company’s ability to meet its liquidity needs is dependent upon generating cash flows from operations in the future in amounts sufficient to meet its obligations and repay its liabilities arising from normal business operations when they come due. There can be no assurance that the Company’s operations will be sufficiently profitable, or that additional funds will be available, to meet its future liquidity needs. Impact of the COVID-19 In March 2020, the World Health Organization declared the COVID-19 “shelter-in-place” “stay-at-home” COVID-19. COVID-19 The sharp decline in airline travel demand due to the COVID-19 COVID-19 COVID-19 COVID-19 While the continued severity and duration of the impacts of the COVID-19 COVID-19 COVID-19 COVID-19 Since a portion of the Company’s revenue is fixed due to the structure of the United capacity purchase agreement, the impact of the COVID-19 COVID-19 The travel restrictions, guidelines and other initiatives adopted to limit the spread of the virus have had, and will continue to have, a material adverse impact on passenger demand for air travel. As a result of this decline in demand, and the subsequent capacity reductions by United, the Company’s approximately 1,271 departures and were 86% and than its departures and scheduled block hours in June 2019, respectively. Cost Reduction Initiatives In response to these developments, during the year ended December 31, 2020 the Company implemented cost reduction initiatives seeking to mitigate the impact of the COVID-19 (1) Reducing or deferring employee-related costs, including: (i) Offering voluntary short-term unpaid leaves to employees and furloughing certain employees, and (ii) Deferring the employer’s portion of employees’ social security tax payments. (2) Reducing other non-employee (i) Delaying planned non-essential (ii) Delaying non-essential (iii) Seeking concessions from third-party suppliers, and (iv) Reducing or suspending certain discretionary spending. Payroll Support In March 2020, the President signed into law the Coronavirus Aid, Relief, and Economic Security Act (CARES Act). In addition to the cost reduction measures discussed above, in April 2020, Air Wisconsin applied to a lender for a $10,000 loan (SBA Loan) under the small business Paycheck Protection Program (PPP) established under the CARES Act and administered by the Small Business Administration (SBA). The entire loan amount was received by Air Wisconsin on April 13, 2020. The application for these funds required Air Wisconsin to certify in good faith that current economic uncertainty made the loan request necessary to support the ongoing operations of Air Wisconsin. Air Wisconsin was also required to certify that the loan funds would be used to retain workers and maintain payroll, or to make mortgage payments, lease payments, and utility payments. The SBA Loan bears interest at a rate of 1.0% per annum. The SBA Loan originally had a two-year non-payroll forgiveness with the lender has not been announced as of the date of filing this Annual Report. Therefore, as of the filing of this Annual Report, the loan has not been forgiven. Air Wisconsin is in compliance with the terms of the SBA Loan. In addition, in April 2020, Air Wisconsin entered into a Payroll Support Program Agreement (PSP-1 42,185 PSP-1 PSP-1 PSP-1 PSP-1 . In December 2020, Congress adopted, and the President signed, the federal Consolidated Appropriations Act of 2021 (PSP Extension Law), Subtitle A of Title IV of Division N of which provides for additional payroll support to eligible air carriers. In March 2021, pursuant to the PSP Extension Law, Air Wisconsin entered into a Payroll Support Program Extension Agreement (the “PSP-2 PSP-1 PSP-2 In March 2021, Congress adopted, and the President signed, the federal American Rescue Plan Act of 2021 (the American Rescue Plan) , Subtitle C of Title VII of which provides further payroll support to eligible air carriers. Air Wisconsin expects to apply for payroll support under the American Rescue Plan and expects that it will be required to enter into an agreement substantially similar to the PSP Agreement and the PSP Agreement, if it receives payroll support under the American Rescue Plan. The proceeds of the Treasury Payroll Support under the CARES Act are recorded in cash and cash equivalents when received and were recognized as a reduction in expense under “CARES Act Payroll Support Program” in the Company’s consolidated statements of operations over the periods that the funds are intended to offset payroll expenses. In 2020 Air Wisconsin received and recognized approximately $42,185 under the Payroll Support Program. In light of the measures discussed above that the Company has implemented to mitigate the impact of the COVID-19

Capacity Purchase Agreement wit

Capacity Purchase Agreement with United	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Capacity Purchase Agreement with United	3. Capacity Purchase Agreement with United In February 2017, Air Wisconsin entered into the United capacity purchase agreement with United Airlines, Inc. to operate up to 65 CRJ-200 two-year

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Property and Equipment	4. Property and Equipment The following presents Air Wisconsin’s aircraft as of December 31, 2020 and 2019. December 31, 2020 Owned Leased CRJ-200 64 0 December 31, 2019 Owned Leased CRJ-200 51 13 As part of an agreement reached in January 2018 Bombardier Inc. (BBD) agreed to pay Air Wisconsin $25,192 in installments through September 2019, provided that BBD had the right to deliver to Air Wisconsin the unencumbered title to certain CRJ-200 On July 1, 2019, BBD exercised its right under the agreement and delivered to Air Wisconsin 14 CRJ-200 Air Wisconsin recorded the 14 CRJ-200 the 2019 statement of operations. The lease termination expense, net of the recording of the assets at fair market value as noted above, included a charge for the following Balance Sheet items at the time the aircraft were acquired in July 2019: • Right-of-use • Unamortized engine overhauls of $9,535, recorded under “Flight property and equipment” on the Balance Sheet, related to the 28 engines acquired as part of the transaction. • Leasehold improvements with a remaining book value of $738 and included on the Balance Sheet as “Flight property and equipment,” related to the 14 acquired aircraft. • Other lease and financing costs incurred at the inception of the aircraft leases and recorded on the Balance Sheet as “Other assets,” had a remaining net book value of $184 at the acquisition date. In January 2020, the Company completed an asset acquisition from Southshore Leasing, LLC (Southshore Leasing), through its affiliates (the Southshore Affiliates and, together with Southshore Leasing, Southshore), of three CRJ-200 In May 2020, Air Wisconsin completed an acquisition of eight CRJ-200 In September 2020, Air Wisconsin completed an acquisition of two CRJ-200

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	5. Income Taxes The income tax provision consists of the following: Year ended December 31, 2020 2019 Current Benefit Federal $ (1,061 ) $ (247 ) State (80 ) (174 ) Total Current Benefit (1,141 ) (421 ) Deferred Expense (Benefit) Federal 3,646 789 State (45 ) (46 ) Total Deferred Expense 3,601 743 Income Tax Expense $ 2,460 $ 322 The following is a reconciliation between a federal income tax rate of 21% in for the years ended December 31, 2020 and 2019 of income before income taxes and the effective tax rate which is derived by dividing the provision for income taxes by the income before the provision for income taxes (in thousands): Year ended December 31, 2020 2019 Computed provision for income taxes at the statutory rate $ 8,867 $ (3,964 ) Increase (decrease) in income taxes resulting from: State income tax provision, net of federal income tax benefit 875 (830 ) Non-deductible 136 241 Refundable credits as a result of CARES Act (936 ) — Valuation allowance changes affecting the provision for income taxes (6,330 ) 5,873 Return to provision adjustments (83 ) (954 ) Other, net (69 ) (44 ) Provision for income taxes $ 2,460 $ 322 As of December 31, 2019, the Company’s deferred tax assets were primarily the result of federal and state net operating loss carryforwards. A valuation allowance of $6,330 was recorded against our gross deferred tax asset balance as of December 31, 2019. For the year ended December 31, 2020, the Company recorded a net valuation allowance release of $6,330, comprising a full-year valuation release on the basis of management’s reassessment of the amount of its deferred tax assets that are more likely than not to be realized. As of each reporting date, management considers new evidence, both positive and negative, that could affect its view of the future realization of deferred tax assets. As of December 31, 2020, the Company achieved three years of cumulative pretax income. In addition, the scheduling of temporary differences and the projection of taxable income led management to believe that there is sufficient positive evidence to conclude that it is more likely than not that deferred tax assets are realizable. It therefore reduced the valuation allowance accordingly. Deferred tax assets and liabilities reflect temporary differences between financial and tax reporting. Significant components of deferred tax assets and liabilities are as follows: December 31, 2020 2019 Deferred Tax Assets Accruals and reserves not currently deductible $ 6,129 $ 6,631 Federal NOL and interest expense limitation carryovers 5,803 13,796 State NOL and interest expense limitation carryovers 476 1,106 Accrued and deferred compensation 1,966 2,888 Prepaid items 745 1,198 Lease liability 1,362 4,052 Contract liability 1,982 2,543 Other 657 1,010 Subtotal before valuation allowance 19,120 33,224 Less: valuation allowance — (6,330 ) Total Deferred Tax Assets 19,120 26,894 Deferred Tax Liabilities Property and equipment (23,268 ) (24,696 ) Right-of-use (2,046 ) (4,791 ) Other (6 ) (6 ) Total Deferred Tax Liabilities (25,320 ) (29,493 ) Net Deferred Income Tax Liabilities $ (6,200 ) $ (2,599 ) At December 31, 2020 and 2019, the Company had federal net operating losses of approximately $27,583 and $60,940, respectively, and state net operating losses of approximately $9,147 and $17,897, respectively. As of December 31, 2020, the estimated effective tax rate applicable to the federal and state net operating losses are 21.0% and 2.8%, respectively. The federal net operating loss is not subject to an expiration date but is subject to an 80% of taxable income limitation after 2020, while the Company expects the state net operating losses to begin to expire in 2024. State net operating losses differ with respect to expiration dates and limitations dependent on state specific regulations. For the years ended December 31, 2020 and 2019, the Company had a federal business interest carryforward of $0 and $4,724, respectively. For the years ended December 31, 2020 and 2019, the Company recorded a valuation allowance of $0 and $6,330, respectively, against federal and state deferred tax assets consisting of net operating loss carryovers and interest expense limitation carryovers. The Company has no ongoing federal or state examinations. Federal tax years 2017, 2018, and 2019 are open to examination. Under ASC Topic 740, the accounting guidance related to uncertain tax positions requires that the impact of a tax position be recognized in the financial statements if that position is more likely than not of being sustained on audit, based on the technical merits of the position. A reconciliation of the beginning and ending amount of unrecognized tax benefits for the years ended December 31, 2020 and 2019 is as follows (in thousands): December 31, 2020 2019 Unrecognized tax benefits at the beginning of the year $ 248 $ 388 Gross decreases – lapse of statute (71 ) (140 ) Unrecognized tax benefits at the end of the year $ 177 $ 248 Interest and penalties in year-end $ 99 $ 121

Debt

Debt	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Debt	6. Debt Long-Term Debt Long-term debt consists of the following (with interest rates as of December 31, 2020 and December 31, 2019): December 31, 2020 2019 Notes due December 31, 2025, 4.0% (a) $ 80,850 $ 86,497 Credit Agreements due through 2022, 5.0% (b) 26,988 34,186 Paycheck Protection Program, 2025 1.0% (c) 10,000 — Total debt 117,838 120,683 Less: current maturities 23,652 12,845 Long-Term Debt $ 94,186 $ 107,838 (a) In December 2018, Air Wisconsin entered into a debt restructuring agreement with a lender (Lender), which held certain senior aircraft notes and subordinated aircraft notes. The senior aircraft notes were exchanged for notes in an aggregate principal amount of $70,000 (Aircraft Notes) and the subordinated aircraft notes were cancelled. Air Wisconsin concluded the restructuring should be classified as a troubled debt restructuring. As such, the future undiscounted interest payments were capitalized as part of the carrying value. As of December 31, 2020 and 2019, the future undiscounted interest payments that are capitalized as part of the debt are $10,850 and $16,497, respectively. (b) Air Wisconsin entered into a credit agreement with the Lender in June 2017 for a principal amount of $14,397, and a second credit agreement in January 2018 for a principal amount of $15,198, which was subsequently amended in December 2018 and again in June 2019 for additional funding of $5,755 and $6,034, respectively, and to extend the maturity date. The loans made by the Lender under these two credit agreements (Other Loans) have maturity dates of December 31, 2020 and June 30, 2022, respectively. (c) In April 2020, in connection with the PPP, Air Wisconsin issued to a lender a promissory note for an aggregate principal amount of $10,000. The amount outstanding under the note may be forgiven under certain circumstances. The Company has recorded the value of the promissory note on a relative fair value basis as $9,106 of long-term debt and $894 of current portion of long-term debt. The Company expects that principal and interest payments on the note will be deferred until August 2021, Air Wisconsin will commence payments in September 2021, and the maturity date will be April 2025 Aircraft Notes In seven separate transactions occurring in 2003 and 2004, Air Wisconsin financed the acquisition of 35 CRJ-200 On December 24, 2018, Air Wisconsin and the Lender entered into a debt restructuring arrangement whereby: (i) The senior aircraft notes were exchanged for the Aircraft Notes in the aggregate principal amount of $70,000; (ii) The aggregate principal balance outstanding under the senior aircraft notes in excess of $70,000, the entire aggregate principal balance outstanding under the subordinated aircraft notes and certain notes payable in 2020, and all interest accrued on the senior aircraft notes and the subordinated aircraft notes prior to the restructuring date, including deferred amounts, was forgiven and deemed paid in full; (iii) The interest rate for the Aircraft Notes was reset to 4.0% per annum; (iv) Commencing on June 30, 2021, there is mandatory amortization of the Aircraft Notes in the aggregate amount of $3,500 semi-annually and certain additional mandatory prepayments based on excess cash flow are required; and (v) The maturity date of the Aircraft Notes was extended to December 31, 2025. The Aircraft Notes are secured by Air Wisconsin’s owned aircraft and certain spare engines and spare parts. Air Wisconsin concluded the restructuring should be classified as a troubled debt restructuring. Accordingly, the carrying value of the restructured debt was reduced to the expected future undiscounted cash flows related to its repayment, which includes future principal and interest payments of $70,000 and $10,850, respectively. Other Credit Agreements In June 2017, Air Wisconsin and the Lender entered into a credit agreement under which Air Wisconsin borrowed $14,397 (the 2017 Credit Agreement). These loans had an interest rate of 5% and a maturity date of December 31, 2020 and were secured by Air Wisconsin’s owned aircraft and certain spare engines and spare parts. These loans were paid in full in December 2020. On January 2018, Air Wisconsin entered into a second credit agreement with the Lender to borrow $15,198 (the 2018 Credit Agreement). In December 2018, the Lender and Air Wisconsin entered into a first amendment to the 2018 Credit Agreement in which the Lender agreed to make an additional loan in the amount of $5,755 in April 2019. In April 2019, Air Wisconsin entered into a second amendment with respect to the 2018 Credit Agreement that extended the due date of one of the payments due in the amount of $7,273 from July 2019 to July 2020. In June 2019, Air Wisconsin entered into a third amendment to the 2018 Credit Agreement that changed the due date of the installment payment of $7,273, due July 2020, to December 2021. The amendment also provided Air Wisconsin the option to make the March 2020 and June 2020 payments under the 2017 Credit Agreement in December 2019, which totaled $7,198. In return, the December 2019 payment under the 2018 Credit Agreement, in the amount of $7,925, would be deferred to be made in two installments of $3,963 each due in March and June of 2022. Air Wisconsin exercised this option. The June 2019 amendment also increased the loan amount of the 2018 Credit Agreement by $6,034, to a total of $26,987, and the amendment extended the maturity date to June 30, 2022 Maturities of long-term debt for the years subsequent to December 31, 2020, are as follows: Fiscal Year Amount 2021 $ 23,652 2022 26,110 2023 11,897 2024 11,644 2025 44,535 Total $ 117,838 The debt agreements include, among other provisions, certain non-financial Long-Term Promissory Note In July 2003, Air Wisconsin financed a hangar through the issuance of $4,275 City of Milwaukee, Wisconsin variable rate Industrial Development Bonds. The bonds mature November 1, 2033. Prior to May 1, 2006, the bonds were secured by a guaranteed investment contract, which was collateralized with cash and interest was payable semiannually on each May 1 and November 1. In May 2006, Air Wisconsin acquired the bonds using the cash collateral. The bonds are reported as long-term investments on the consolidated balance sheets. The hangar is accounted for as a right-of-use

Lease Obligations

Lease Obligations	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Lease Obligations	7. Lease Obligations Effective January 1, 2019, the Company adopted Topic 842. Air Wisconsin leases property and training simulators under operating leases. For leases with durations longer than 12 months, the Company recorded the related operating lease right-of-use The Company has operating leases for facility space including office space and maintenance facilities. The remaining lease terms for facility space vary from 20 months to 13 years. The Company’s operating leases with lease rates that are variable based on operating costs, use of the facilities or other variable factors are excluded from the Company’s right-of-use As of December 31, 2020, the Company’s right-of-use The table below presents operating lease related terms and discount rates as of December 31, 2020: Weighted-average remaining lease term 4.94 years Weighted-average discount rate 6.99 % Components of lease costs were as follows for the years ended December 31, 2020 2019 Operating lease cost $ 9,326 $ 27,624 Short-term lease cost 1,662 4,331 Variable lease cost (994 ) 182 Lease termination expense 1,299 19,353 Total lease cost $ 11,293 $ 51,490 As of December 31, 2020, Air Wisconsin leased or subleased certain training simulators and facilities for terms of greater than 12 months. Rent expense recorded under these leases was $11,293 and $51,490 in the years ended December 31, 2020 and 2019, respectively. The following table summarizes the future minimum rental payments required under operating leases that had initial or remaining non-cancelable Fiscal Year Amount 2021 1,766 2022 1,778 2023 1,513 2024 1,103 2025 390 Thereafter 579 Total lease payments 7,129 Less imputed interest (1,417 ) Total lease liabilities $ 5,712

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	8. Commitments and Contingencies Legal Matters The Company is subject to certain legal actions, which it considers routine to its business activities. As of December 31, 2020, the Company believes, after consultation with legal counsel, that the ultimate outcome of such legal matters, whether individually or in the aggregate, is not likely to have a material adverse effect on the Company’s financial position, liquidity, or results of operations. Treasury Audit The Treasury’s Office of Inspector General (OIG) commenced a routine audit in connection with Air Wisconsin’s receipt of funds under the Payroll Support Program. The audit focused, among other things, on certain calculations used to determine the amount of Treasury Payroll Support Air Wisconsin was entitled to receive under the program. Air Wisconsin has disputed in good faith the Treasury’s interpretation of varying definitions and other provisions among Air Wisconsin’s application for Treasury Payroll Support, Treasury’s guidance regarding the Payroll Support Program and the PSP-1 PSP-2 PSP-2 PSP-1 PSP-2 Standby Letters of Credit As of December 31, 2020, Air Wisconsin had five outstanding letters of credit in the aggregate amount of $348 to guarantee the performance of its obligations under certain lease agreements and insurance policies. Air Wisconsin maintains a credit facility of $810 for the issuance of such letters of credit as needed to support its operations. Air Wisconsin’s restricted cash secures the credit facility. Cash Obligations The following table sets forth our cash obligations as of December 31, 2020: Payment Due for Year Ending December 31, (in thousands) Total 2021 2022 2023 2024 2025 Thereafter Aircraft Notes principal $ 70,000 $ 7,000 $ 7,000 $ 7,000 $ 7,000 $ 42,000 $ — Aircraft Notes interest $ 10,850 $ 2,730 $ 2,450 $ 2,170 $ 1,890 $ 1,610 $ — Other Loans principal $ 36,988 $ 13,922 $ 16,660 $ 2,727 $ 2,754 $ 925 $ — Other Loans interest $ 1,853 $ 1,262 $ 378 $ 51 $ 24 $ 138 $ — Operating lease obligations $ 7,129 $ 1,766 $ 1,778 $ 1,513 $ 1,103 $ 390 $ 579 Total $ 126,820 $ 26,680 $ 28,266 $ 13,461 $ 12,771 $ 45,063 $ 579 The principal amount of the Aircraft Notes is payable in semi-annual installments of $3,500 commencing June 30, 2021, with certain additional amounts payable based on excess cash flow. No excess cash flow payments are anticipated in the above table. As of December 31, 2020, all of the Company’s long-term debt was subject to fixed interest rates.

Retirement Plans

Retirement Plans	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
Retirement Plans	9. Retirement Plans The Company has defined contribution retirement plans that cover substantially all employees. The Company contributes to these plans. Total expense under all plans for 2020 and 2019 was $3,764 and $4,467, respectively.

Related-Party Transactions

Related-Party Transactions	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Related-Party Transactions	10. Related-Party Transactions For the years ended December 31, 2020 and 2019, the Company paid $390 and $3,979, respectively, pursuant to certain aircraft and engine leases with related parties and for other professional services. Southshore leased aircraft and engines to Air Wisconsin pursuant to various operating lease agreements from April 2010 through January 2020. In the year ended December 31, 2020, Air Wisconsin paid a total of approximately $150 to Southshore, consisting of approximately $66 for the lease of three aircraft and approximately $84 for the lease of additional engines to support Air Wisconsin’s operations. In the year ended December 31, 2019, Air Wisconsin paid a total of approximately $3,739 to Southshore, consisting of approximately $1,878 for the lease of three aircraft, a total of approximately $1,661 for the lease of additional engines, and $200 for the purchase of two previously leased airframes. In January 2020, the Company completed an acquisition from Southshore of three CRJ-200 Following the adjustment of the Conversion Price to $0.15091 per share, effective as of January 7, 2021, in accordance with the Conversion Cap set forth in the Certificate of Designations, the Series C Preferred remains convertible into an aggregate of 16,500 From time to time, Air Wisconsin has also contracted for services to be performed on certain assets held by Southshore used in Air Wisconsin’s operations and has received reimbursement from Southshore at the cost of such services. Because Air Wisconsin acted as an agent or an intermediary in facilitating such transactions, the amounts of any such transactions are not included in the amounts described above. Resource Holdings Associates (Resource Holdings) has provided AWAC and Air Wisconsin with financial advisory and management services pursuant to an agreement entered into in January 2012. AWAC has paid a recurring monthly fee of $20 in exchange for these financial advisory and management services since January 2012. AWAC paid a total of $240 to Resource Holdings in both 2020 and 2019.

Collective Bargaining Agreement

Collective Bargaining Agreements	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
Collective Bargaining Agreements	11. Collective Bargaining Agreements Air Wisconsin has five collective bargaining units. The Airline Pilots Association (ALPA) represents pilots. The Association of Flight Attendants-CWA AFL-CIO As of December 31, 2020, Air Wisconsin was in negotiations with the union that represents mechanics and will be in negotiations with the union that represents the dispatchers. Air Wisconsin is in mediated negotiations with the IAMAW representing the mechanics. The agreements with the TWU representing the dispatchers was amendable on November 1, 2020, however Air Wisconsin and the union have not started the negotiation process. Air Wisconsin believes the resolution of its negotiations will not have a material impact on its financial position or operations. Amendable dates for each bargaining unit are: Bargaining Unit Amendable Date Pilots November 21, 2022 Dispatchers November 1, 2020 Mechanics October 7, 2015 Technical store clerks September 20, 2022 Flight attendants October 1, 2022

Earnings Per Share and Equity

Earnings Per Share and Equity	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Earnings Per Share and Equity	12. Earnings Per Share Calculations of net income per common share were as follows (in thousands, except per share data): 2020 2019 Net income (loss) $ 39,763 (19,214 ) Preferred stock dividends 759 — Net income (loss) applicable to common stockholders 39,004 (19,214 ) Weighted average common shares outstanding Shares used in calculating basic earnings per share 54,863 54,863 Stock options 559 — Series C Preferred 15,777 — Shares used in calculating diluted earnings per share 71,199 54,863 Earnings (loss) allocated to common stockholders per common share Basic $ 0.71 (0.35 ) Diluted $ 0.56 (0.35 ) Basic earnings (loss) per share of common stock is computed by dividing the net income (loss) applicable to common stockholders by the weighted average number of shares of common stock outstanding during the period. Diluted earnings per share is computed by dividing net income by the weighted average number of shares outstanding assuming conversion of the 2015 Stock Option and Series C Preferred. In loss periods, dilutive shares associated with the 2015 Stock Option and the Series C Preferred were not included in the calculation above, as they would have an anti-dilutive effect on the calculation of earnings per share. For additional information, refer to Note 13. Series C Preferred In January 2020, the Company issued 4,000 shares of the Series C Preferred. The rights, preferences, privileges, qualifications, restrictions and limitations relating to the Series C Preferred are set forth in the Certificate of Designations, Preferences and Rights of Series C Convertible Redeemable Preferred Stock (Certificate of Designations), which the Company filed with the Secretary of State of the State of Delaware. The Series C Preferred accrues dividends at the rate of 6.0% per annum, which are cumulative and compound quarterly to the extent dividends have not been declared by the Board of Directors and paid by the Company (Preferential Dividends). From and after December 31, 2023, upon the election of holders of a majority of the outstanding Series C Preferred, the rate of the Preferential Dividends shall be increased by an additional 1.0% per annum per share for each and every six-month Each share of Series C Preferred is initially convertible, at any time after issuance, into that number of shares of common stock determined by dividing the then applicable Series C Liquidation Amount (defined below) by $0.80, subject to certain adjustments set forth in the Certificate of Designations (Conversion Price). One of the requirements of the Certificate of Designations is that the Conversion Price be adjusted to equal the Weighted Average Price (as defined in the Certificate of Designations) of the common stock during the Reporting Adjustment Period. The “Reporting Adjustment Period” is the first 90-trading day The conversion of Series C Preferred is subject to a limitation on the number of shares of the common stock that may be issued upon conversion of Series C Preferred equal to the sum of (a) 16,500, plus (b) the quotient of (i) the aggregate amount of all accrued and unpaid Preferential Dividends divided by (ii) $0.80, plus (c) the quotient of (i) the number of shares of Series C Preferred issued as PIK Dividends multiplied by the Series C Issue Price, divided by (ii) $0.80. Any outstanding shares of Series C Preferred that may not be converted pursuant to the limitation described herein (Conversion Cap Excess Shares), from and after December 31, 2022, in addition to the Preferential Dividends, shall accrue cumulative quarterly dividends of an amount per share equal to 0.5% of the Series C Liquidation Amount (as defined below) of each outstanding Conversion Cap Excess Share in the first quarter after December 31, 2022, and increasing an additional 0.5% of the Series C Liquidation Amount in each subsequent quarter (Conversion Cap Excess Dividends). In the event of any liquidation, dissolution or winding up of the Company or a sale of the Company, the Series C Preferred shall be entitled to receive, prior and in preference to any distribution of any assets of the Company to the common stock or other junior capital stock, an amount equal to the Series C Issue Price, plus an amount equal to all accrued but unpaid Preferential Dividends, Conversion Cap Excess Dividends and any other accrued but unpaid dividends (Series C Liquidation Amount). At any time following the earliest of (a) the date that is four years after the earlier of the Reporting Date (as defined in the Certificate of Designations) or (i) any merger or consolidation to which the Company is a constituent party and to which one or more third-party entities, unaffiliated with the Company, are constituent parties or (ii) any transaction or series of related transactions pursuant to which the Company shall issue or sell a number of shares of common stock greater than 5.0% of the number of shares of common stock then outstanding, (b) the date the Dividend Ratchet has been initiated, (c) any time that fewer than 800 shares of Series C Preferred are outstanding, and (d) December 31, 2024, the Company shall have the right to redeem all, but not less than all, of the shares of Series C Preferred then outstanding at a per share price equal to the then current Series C Liquidation Amount (Redemption Price). At any time after the outstanding shares of Series C Preferred are deemed Conversion Cap Excess Shares, the Company shall have the right to redeem all, but not less than all, of the Conversion Cap Excess Shares then outstanding at the Redemption Price. In January 2020, the Company also entered into an Investors’ Rights Agreement with Southshore, pursuant to which the Company agreed, if requested by Southshore at any time following the 180-day period S-1 On April 15, 2020, June 30, 2020, September 29, 2020 and December 30, 2020, the Board of Directors declared dividends of $165, $198, $198 and $198, respectively, on the Series C Preferred, which were paid on April 20, 2020, July 1, 2020, September 30, 2020, and December 31, 2020, respectively. Based on the applicable accounting guidance, the Company is required to apply the “if-converted” method to the Series C Preferred to determine the weighted average number of shares outstanding for purposes of calculating the net income (loss) per share of common stock. However, conversion is not assumed for purposes of computing diluted earnings per share if the effect would be anti-dilutive. As of December 31, 2020, pursuant to the Certificate of Designations, the Series C Preferred was convertible into an aggregate of 16,500 shares of common stock. Following the adjustment of the conversion price of the Series C Preferred effective as of January 7, 2021, the Series C Preferred is convertible into an aggregate of 16,500,000 shares of common stock, representing approximately % of the fully diluted shares of capital stock of the Company (assuming the full conversion of the Series C Preferred into common stock). The Company accounts for its Series C Preferred in accordance with the guidance in ASC Topic 480, Distinguishing Liabilities from Equity

Stock Options

Stock Options	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Stock Options	13. Stock Options 2015 Stock Option In 2015, the Company issued a stock option (the 2015 Stock Option) to purchase 558,835 shares of the common stock of the Company at an exercise price of $0.21386 per share. The value of the 2015 Stock Option at the date of grant was $0.07 per share based on a life of 7.0 years, a risk-free interest rate of 2.01% and expected volatility of 157.1%. The 2015 Stock Option was the only stock option outstanding as of December 31, 2020 and 2019. After July 9, 2019, the 2015 Stock Option became fully exercisable. Prior to that date it could only be exercised based on the occurrence of certain events. The 2015 Stock Option terminates on the earlier to occur of July 9, 2022 or certain corporate transactions.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	12 Months Ended
	Dec. 31, 2020
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	14. Supplemental Cash Flow Information Cash payments for interest for the years ended December 31, 2020 and 2019 were $7,311 and $1,841, respectively. Cash payments for income taxes for the years ended December 31, 2020 and 2019 amounted to $(1,035) and $39, respectively. Cash payments included in the measurement of lease liabilities related to operating leases amount to $5,398 and $29,502 for the years ended December 31, 2020 and 2019 respectively. In the year ended December 31, 2019 the Company also recorded a fair market value of $15,832 for 14 aircraft acquired in a non-cash

Intangible Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	15. Intangible Assets Intangible assets at December 31, 2020 and 2019 consist of the following (in thousands): December 31, 2020 2019 Gross Carrying Amount Gross Carrying Amount Trade names and air carrier certificate 5,300 5,300 Total $ 5,300 $ 5,300

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	16. Subsequent Events The Company evaluated its December 31, 2020, financial statements for subsequent events through April 1, 2021, the date the financial statements were available to be issued. The following subsequent events are noted: • Refer to Note 2 for certain subsequent events regarding the impact of the COVID-19 pandemic • Through notices given on January 29, 2021 pursuant to the WARN Act, Air Wisconsin informed approximately 150 pilots (all of whom had received the prior WARN Act notices) that they might be furloughed on April 1, 2021, due to the COVID-19 • In March 2021, Congress adopted, and the President signed, the federal American Rescue Plan, which provides further payroll support to eligible air carriers. Air Wisconsin expects to apply for payroll support under such statute and expects that it will be required to enter into an agreement substantially similar to the PSP-1 PSP-2 • Effective January 1, 2021, the Board of Managers of Air Wisconsin appointed Liam Mackay to serve as its Chief Financial Officer. In connection with his appointment, Air Wisconsin entered into an employment agreement with Mr. Mackay. Gregg Garvey, the current Senior Vice President, Chief Accounting Officer and Treasurer of Air Wisconsin, will continue to serve as the Company’s Principal Financial and Accounting Officer. • Effective March 30, 2021, the Company’s board of directors adopted a stock repurchase program pursuant to which the Company may initially repurchase up to $1,000 of shares of its common stock during the first calendar month of the program, subject to an automatic increase of per calendar month thereafter. The Company is not obligated under the program to acquire any particular number or value of shares and can suspend or terminate the program at any time.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (GAAP) and include the accounts of Harbor Diversified, Inc. and subsidiaries (collectively, the Company). Harbor Diversified, Inc. is a non-operating holding company is a non-operating entity with
Description of Operations	Description of Operations The Company has principal lines of business focused on (1) providing air transportation through Air Wisconsin (airline business), (2) acquiring flight equipment for the purpose of leasing the equipment to Air Wisconsin and (3) providing flight equipment financing to Air Wisconsin. The airline business is operated entirely through Air Wisconsin, which is an independent regional air carrier that is engaged in the business of providing scheduled passenger service under a capacity purchase agreement (the United capacity purchase agreement) with United Airlines, Inc. (United) that was entered into in February 2017 and amended in October 2020. For additional information, refer to Note 3, Capacity Purchase Agreement with United. Air Wisconsin operates as a United Express carrier with a significant presence at both Chicago O’Hare and Washington-Dulles, two of United’s key domestic hubs.
Segment Reporting	Segment Reporting Operating segments are defined as components of an enterprise about which separate financial information is available that is evaluated regularly by the chief operating decision maker in deciding how to allocate resources and in assessing operating performance. In consideration of Accounting Standards Codification (ASC) 280, “ Segment Reporting As further discussed below, substantially all of our operating revenue in 2020 and 2019 was derived from operations associated with United.
Contract and Other Revenues	Contract and Other Revenues The Company recognizes revenue under the United capacity purchase agreement over time as services are provided. United pays the Company a fixed rate for each departure and block hour (measured from takeoff to landing, including taxi time), and a fixed amount per aircraft per day, with additional incentives primarily based on flight completion, on-time The United capacity purchase agreement includes weekly provisional cash payments based on a projected level of flying each month. The Company and United subsequently reconcile these payments to the actual completed flight activity on a monthly basis. Under the United capacity purchase agreement, the Company is eligible to receive incentive compensation upon the achievement of certain performance criteria (provided that, pursuant to the amendment to the United capacity purchase agreement, no incentive or penalty payments were made for the period from April 1, 2020 through September 30, 2020). The incentives are defined in the agreement and are determined and measured on a monthly basis. At the end of each month during the term of the agreement, the Company calculates the incentives achieved during that period and recognizes revenue accordingly, subject to the variable constraint guidance under Financial Accounting Standards Board (FASB) Accounting Standards Update (ASU) No. 2014-09, Revenue from Contracts with Customers As discussed above, under the United capacity purchase agreement, Air Wisconsin is paid a fixed amount per aircraft per day for each month during the term of the agreement. In accordance with GAAP, the Company recognizes revenue related to the fixed payments on a proportional basis taking into account the number of flights actually completed in that period relative to the number of flights expected to be completed in subsequent periods during the remaining term of the agreement. Due to the material decrease in completed flights for the year ended December 31, 2020 from historical levels and anticipated future levels in periods within the remaining contract term, Air Wisconsin determined that the amount of the fixed payments it received was disproportionately high relative to anticipated fixed revenue for future periods due to fewer flights completed in the year ended December 31, 2020. Air Wisconsin non-refundable The amount of revenue recognized for the year ended December 31, 2020 that was previously recorded as a contract liability is $7,116. In October 2020, Air Wisconsin entered into an amendment to the United capacity purchase agreement (CPA amendment), which, among other things, provided for the payment or accrual of certain amounts by United to Air Wisconsin based on certain scheduling benchmarks. In conjunction with the significant reduction in departures and block hours caused by the COVID-19 pandemic, and as a result of the CPA amendment, management determined, using a significant amount of judgement, that from an accounting perspective, a new performance obligation was created by United requiring Air Wisconsin to stand ready to deliver flight services. Air Wisconsin determined, using the expected cost plus a margin method, that the United stand ready rate represents the relative stand-alone selling price of the performance obligation. The stand ready performance obligation will be recognized over time on a straight line basis based on the number of unscheduled block hours below a minimum threshold at the stand ready rate as determined by the CPA amendment. For the year ending December 31, 2020, Air Wisconsin recorded $21,392 in revenue related to this performance obligation. This amount was recorded in tong-term notes receivable on the balance sheet as of December 31, 2020. As part of the CPA amendment, Air Wisconsin also settled outstanding issues, including the opening and closing of maintenance bases. United agreed to accrue a liability to Air Wisconsin in the amount of $11,048 along with a cash settlement of $670. These amounts were recognized using a cumulative catchup adjustment based on prior and future expected departures. In total, Air Wisconsin recognized revenue of $7,307 and deferred the remaining portion which will be recognized in proportion to future departures. These accrued amounts contain a significant financing component and any interest income is separately reported in the statement of operations. Further, the accrued amounts are evidenced by notes receivable payable by United to Air Wisconsin. As of December 31, 2020, these notes totaled 2020, interest receivable on these notes totaled $309. United makes provisional cash payments to the Company during each month of service based on monthly flight schedules. These provisional cash payments are reconciled based on actual completed flights after each month’s flight activity is completed. As of December 31, 2020, United owed Air Wisconsin $1,180 which is recorded in “Accounts receivable less allowances” on the balance sheet. Other revenues are immaterial and primarily consist of the sales of parts to other airlines. The transaction price for the sale of these parts generally is fair market value.
Cash and Cash Equivalents	Cash and Cash Equivalents Investments and deposits with a maturity of three months or less when acquired and money market funds are considered cash and cash equivalents.
Restricted Cash	Restricted Cash Restricted cash represents amounts escrowed in an interest-bearing account relating to the Company’s letters of credit.
Spare Parts and Supplies	Spare Parts and Supplies Expendable parts are stated at average cost less an obsolescence allowance. The Company provides for an allowance for obsolescence after considering the useful life of the aircraft fleet, the estimated cost of expendable parts expected to be on hand at the end of the useful life and the estimated salvage value of the parts. This allowance is based on management estimates and is subject to change. Expendable parts are charged to expense when used. Expendable parts that are repairable are returned to inventory at the average cost of comparable parts, less a reserve for scrap. Supplies are stated at average cost.
Property and Equipment and Depreciation	Property and Equipment and Depreciation Property and equipment are stated at cost and depreciated over their useful lives to their estimated residual values using the straight-line method as follows: Assets Depreciable Life Current Residual Value Aircraft 7 years $ 50,000 Rotable parts 7 years 10 % Spare engines 7 years $ 25,000 Ground equipment up to 10 years 0 % Office equipment up to 10 years 0 % Leasehold improvements Shorter of asset or lease life 0 % Air Wisconsin’s capitalized engine maintenance costs are amortized over their estimated useful life measured in remaining engine cycles to the next scheduled shop event. Lotus’ engine maintenance costs are expensed. Depreciation expense in 2020 and 2019 was $25,719 and $23,578, respectively, and is included in depreciation, amortization, and obsolescence in the accompanying consolidated statements of operations.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company evaluates long-lived assets for potential impairment and records impairment losses on long-lived assets when events and circumstances indicate the assets might be impaired and the undiscounted cash flows estimated to be generated by those assets are less than their carrying amounts. Impairment losses are measured by comparing the fair value of the assets to their carrying amounts. In determining the need to record impairment charges, the Company is required to make certain estimates and assumptions regarding such things as the current fair market value of the assets and future net cash flows to be generated by the assets. If there are subsequent changes to these estimates or assumptions, or if actual results differ from these estimates or assumptions, such changes could impact the financial statements in the future. The Company conducted a qualitative impairment assessment of its long-lived assets and determined that no quantitative impairment tests were needed as of December 31, 2020.
Impairment of Intangible Assets	Impairment of Intangible Assets Indefinite-lived intangible assets are not subject to amortization but are subject to an annual assessment for impairment by applying a fair-value-based test. Since Air Wisconsin’s trade names and air carrier certificate have indefinite lives, there is no amortization. The Company evaluated these assets for impairment and determined that no impairment existed as of December 31, 2020 or 2019.
Maintenance	Maintenance The Company operates its aircraft under a continuous inspection and maintenance program. The normal cost of recurring maintenance is expensed when incurred except for planned major maintenance activities for engines where the deferral method of accounting is applied.
Income Taxes	Income Taxes The Company utilizes the asset and liability method for accounting for income taxes. Under the asset and liability method, deferred tax assets and liabilities are determined based upon the estimated future tax effects of differences between the financial statement and tax basis of assets and liabilities, as measured by the current applicable tax rates. Deferred tax expense represents the result of changes in deferred tax assets and liabilities. As required by the uncertain tax position guidance, the Company recognizes the financial statement benefit of a tax position only after determining that the relevant tax authority would more-likely-than-not more-likely-than-not The Company is subject to federal, state and local income taxes in the United States and various states. Tax regulations within each jurisdiction are subject to the interpretation of the related tax laws and regulations and require significant judgment to apply. The Company is no longer subject to U.S. federal income tax examinations for the years prior to 2017. With a few exceptions, the Company is no longer subject to state or local income tax examinations for the years prior to 2016. As of December 31, 2020, the Company had no outstanding tax examinations. The Company recognizes interest and penalties related to unrecognized tax benefits in income tax expense for all periods presented. The Company had accrued $99 and $121 for the payment of interest and penalties at December 31, 2020 and 2019, respectively.
Comprehensive Income	Comprehensive Income The Company does not have any components of comprehensive income and, as of December 31, 2020 and 2019, comprehensive income is equal to net income reported in the consolidated statements of operations.
Concentration of Credit Risk	Concentration of Credit Risk The Company at times has had bank deposits in excess of the Federal Deposit Insurance Corporation (FDIC) insurance limit.
Concentration of Customer Risk	Concentration of Customer Risk Substantially all the Company’s revenues in the years ended December 31, 2020 and 2019 were derived from the United capacity purchase agreement. Refer to Note 3 for additional information.
Estimates and Assumptions	Estimates and Assumptions The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ materially from those estimates.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company’s financial instruments include cash and cash equivalents, restricted cash, accounts receivable, notes receivable, long-term investments, accounts payable, and long-term debt. The Company believes the carrying amounts of these financial instruments are a reasonable estimate of their fair value because of the short-term nature of such instruments, or, in the case of long-term debt, because of interest rates available to the Company for similar obligations. Long-term investments are held-to-maturity Fair value is defined as the price that would be received to sell an asset, or paid to transfer a liability, in an orderly transaction between market participants at the measurement date (that is, an exit price). ASC 820 establishes a three-tier fair value hierarchy, which prioritizes inputs used in fair value. The tiers are as follows: Level 1 - Quoted market prices in active markets for identical assets or liabilities. Level 2 - Inputs other than Level 1 inputs that are either directly or indirectly observable. Level 3 - Unobservable inputs developed using the Company’s estimates and assumptions, which reflect those that market participants would use. The determination of where an asset or liability falls in the hierarchy requires significant judgment. The Company evaluates these determinations annually, and it is possible that an asset or liability may be classified differently from year to year. However, the Company expects that changes in classifications between levels will be rare. The Company classifies money market funds and deposits as Level 1 and long-term investments as
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) (Topic 842). ASU 2016-02 is intended to improve financial reporting of leasing transactions by requiring organizations that lease assets to recognize assets and liabilities for the rights and obligations created by leases on the balance sheet. The accounting update also requires additional disclosures surrounding the amount, timing, and uncertainty of cash flows arising from leases. The Company adopted Topic 842 effective January 1, 2019 and elected the package of transition practical expedients for expired or existing contracts, which does not require reassessment of: (1) whether any of the Company’s contracts are or contain leases, (2) lease classification, and (3) initial direct costs. In July 2018, the FASB issued ASU No. 2018-11, “Targeted Improvements – Leases (Topic 842).” This update provides an optional approach that allows entities to elect to apply the standard using the modified retrospective approach at its effective date, versus recasting the prior years as presented. If this adoption method is elected, an entity would recognize a cumulative-effect adjustment to the opening balance of retained earnings in the year of adoption. The Company elected this adoption method, however, an adjustment was not necessary to opening retained earnings. Additionally, the Company’s adoption of Topic 842 did not have a significant impact on the recognition, measurement or presentation of lease revenue and lease expenses within the financial statements of operations and statement of cash flows. The Company’s prepaid aircraft rents and accrued aircraft rents that were separately stated in the Company’s December 31, 2018 balance sheet have been classified as a component of the Company’s right-of-use assets effective January 1, 2019. As a result of the adoption of the new lease accounting guidance, the Company recognized the following ROU assets and lease liabilities as of January 1, 2019: Right-of-use assets – operating leases $ 70,892 Lease liabilities – operating leases $ 40,921 In August 2018, the FASB issued ASU 2018-13, Fair 2018-13 Recent Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses Measurement of Credit Losses on Financial Instruments 2016-13). 2016-13 2016-13 2016-13 In August 2020, the FASB issued ASU No. 2020-06, Debt 470-20); 815-40); 2020-06). 2020-06 2020-06
Reclassifications	Reclassification In accordance with ASU 2016-18,

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Schedule of Property and Equipment Useful lives	Property and equipment are stated at cost and depreciated over their useful lives to their estimated residual values using the straight-line method as follows: Assets Depreciable Life Current Residual Value Aircraft 7 years $ 50,000 Rotable parts 7 years 10 % Spare engines 7 years $ 25,000 Ground equipment up to 10 years 0 % Office equipment up to 10 years 0 % Leasehold improvements Shorter of asset or lease life 0 %
Summary of ROU assets and lease liabilities	As a result of the adoption of the new lease accounting guidance, the Company recognized the following ROU assets and lease liabilities as of January 1, 2019: Right-of-use assets – operating leases $ 70,892 Lease liabilities – operating leases $ 40,921

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Schedule of Company's Aircrafts	The following presents Air Wisconsin’s aircraft as of December 31, 2020 and 2019. December 31, 2020 Owned Leased CRJ-200 64 0 December 31, 2019 Owned Leased CRJ-200 51 13

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Summary of Income Tax Provision	The income tax provision consists of the following: Year ended December 31, 2020 2019 Current Benefit Federal $ (1,061 ) $ (247 ) State (80 ) (174 ) Total Current Benefit (1,141 ) (421 ) Deferred Expense (Benefit) Federal 3,646 789 State (45 ) (46 ) Total Deferred Expense 3,601 743 Income Tax Expense $ 2,460 $ 322
Schedule of Effective Income Tax Rate Reconciliation	The following is a reconciliation between a federal income tax rate of 21% in for the years ended December 31, 2020 and 2019 of income before income taxes and the effective tax rate which is derived by dividing the provision for income taxes by the income before the provision for income taxes (in thousands): Year ended December 31, 2020 2019 Computed provision for income taxes at the statutory rate $ 8,867 $ (3,964 ) Increase (decrease) in income taxes resulting from: State income tax provision, net of federal income tax benefit 875 (830 ) Non-deductible 136 241 Refundable credits as a result of CARES Act (936 ) — Valuation allowance changes affecting the provision for income taxes (6,330 ) 5,873 Return to provision adjustments (83 ) (954 ) Other, net (69 ) (44 ) Provision for income taxes $ 2,460 $ 322
Components of Deferred Tax Assets and Liabilities	Significant components of deferred tax assets and liabilities are as follows: December 31, 2020 2019 Deferred Tax Assets Accruals and reserves not currently deductible $ 6,129 $ 6,631 Federal NOL and interest expense limitation carryovers 5,803 13,796 State NOL and interest expense limitation carryovers 476 1,106 Accrued and deferred compensation 1,966 2,888 Prepaid items 745 1,198 Lease liability 1,362 4,052 Contract liability 1,982 2,543 Other 657 1,010 Subtotal before valuation allowance 19,120 33,224 Less: valuation allowance — (6,330 ) Total Deferred Tax Assets 19,120 26,894 Deferred Tax Liabilities Property and equipment (23,268 ) (24,696 ) Right-of-use (2,046 ) (4,791 ) Other (6 ) (6 ) Total Deferred Tax Liabilities (25,320 ) (29,493 ) Net Deferred Income Tax Liabilities $ (6,200 ) $ (2,599 )
Schedule of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of unrecognized tax benefits for the years ended December 31, 2020 and 2019 is as follows (in thousands): December 31, 2020 2019 Unrecognized tax benefits at the beginning of the year $ 248 $ 388 Gross decreases – lapse of statute (71 ) (140 ) Unrecognized tax benefits at the end of the year $ 177 $ 248 Interest and penalties in year-end $ 99 $ 121

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Schedule of Long-term Debt	Long-term debt consists of the following (with interest rates as of December 31, 2020 and December 31, 2019): December 31, 2020 2019 Notes due December 31, 2025, 4.0% (a) $ 80,850 $ 86,497 Credit Agreements due through 2022, 5.0% (b) 26,988 34,186 Paycheck Protection Program, 2025 1.0% (c) 10,000 — Total debt 117,838 120,683 Less: current maturities 23,652 12,845 Long-Term Debt $ 94,186 $ 107,838 (a) In December 2018, Air Wisconsin entered into a debt restructuring agreement with a lender (Lender), which held certain senior aircraft notes and subordinated aircraft notes. The senior aircraft notes were exchanged for notes in an aggregate principal amount of $70,000 (Aircraft Notes) and the subordinated aircraft notes were cancelled. Air Wisconsin concluded the restructuring should be classified as a troubled debt restructuring. As such, the future undiscounted interest payments were capitalized as part of the carrying value. As of December 31, 2020 and 2019, the future undiscounted interest payments that are capitalized as part of the debt are $10,850 and $16,497, respectively. (b) Air Wisconsin entered into a credit agreement with the Lender in June 2017 for a principal amount of $14,397, and a second credit agreement in January 2018 for a principal amount of $15,198, which was subsequently amended in December 2018 and again in June 2019 for additional funding of $5,755 and $6,034, respectively, and to extend the maturity date. The loans made by the Lender under these two credit agreements (Other Loans) have maturity dates of December 31, 2020 and June 30, 2022, respectively. (c) In April 2020, in connection with the PPP, Air Wisconsin issued to a lender a promissory note for an aggregate principal amount of $10,000. The amount outstanding under the note may be forgiven under certain circumstances. The Company has recorded the value of the promissory note on a relative fair value basis as $9,106 of long-term debt and $894 of current portion of long-term debt. The Company expects that principal and interest payments on the note will be deferred until August 2021, Air Wisconsin will commence payments in September 2021, and the maturity date will be April 2025
Schedule of Maturities of Long-Term Debt	Maturities of long-term debt for the years subsequent to December 31, 2020, are as follows: Fiscal Year Amount 2021 $ 23,652 2022 26,110 2023 11,897 2024 11,644 2025 44,535 Total $ 117,838

Lease Obligations (Tables)

Lease Obligations (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Summary of Operating Lease Related Terms and Discount Rates	The table below presents operating lease related terms and discount rates as of December 31, 2020: Weighted-average remaining lease term 4.94 years Weighted-average discount rate 6.99 %
Schedule of Component of Lease Cost	Components of lease costs were as follows for the years ended December 31, 2020 2019 Operating lease cost $ 9,326 $ 27,624 Short-term lease cost 1,662 4,331 Variable lease cost (994 ) 182 Lease termination expense 1,299 19,353 Total lease cost $ 11,293 $ 51,490
Schedule of Future Minimum Lease Payments Under Non-Cancelable Operating Leases	The following table summarizes the future minimum rental payments required under operating leases that had initial or remaining non-cancelable Fiscal Year Amount 2021 1,766 2022 1,778 2023 1,513 2024 1,103 2025 390 Thereafter 579 Total lease payments 7,129 Less imputed interest (1,417 ) Total lease liabilities $ 5,712

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Schedule of Cash Obligations	The following table sets forth our cash obligations as of December 31, 2020: Payment Due for Year Ending December 31, (in thousands) Total 2021 2022 2023 2024 2025 Thereafter Aircraft Notes principal $ 70,000 $ 7,000 $ 7,000 $ 7,000 $ 7,000 $ 42,000 $ — Aircraft Notes interest $ 10,850 $ 2,730 $ 2,450 $ 2,170 $ 1,890 $ 1,610 $ — Other Loans principal $ 36,988 $ 13,922 $ 16,660 $ 2,727 $ 2,754 $ 925 $ — Other Loans interest $ 1,853 $ 1,262 $ 378 $ 51 $ 24 $ 138 $ — Operating lease obligations $ 7,129 $ 1,766 $ 1,778 $ 1,513 $ 1,103 $ 390 $ 579 Total $ 126,820 $ 26,680 $ 28,266 $ 13,461 $ 12,771 $ 45,063 $ 579

Earnings Per Share and Equity (

Earnings Per Share and Equity (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Schedule of Calculations of Net Income Per Common Share	Calculations of net income per common share were as follows (in thousands, except per share data): 2020 2019 Net income (loss) $ 39,763 (19,214 ) Preferred stock dividends 759 — Net income (loss) applicable to common stockholders 39,004 (19,214 ) Weighted average common shares outstanding Shares used in calculating basic earnings per share 54,863 54,863 Stock options 559 — Series C Preferred 15,777 — Shares used in calculating diluted earnings per share 71,199 54,863 Earnings (loss) allocated to common stockholders per common share Basic $ 0.71 (0.35 ) Diluted $ 0.56 (0.35 )

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets	Intangible assets at December 31, 2020 and 2019 consist of the following (in thousands): December 31, 2020 2019 Gross Carrying Amount Gross Carrying Amount Trade names and air carrier certificate 5,300 5,300 Total $ 5,300 $ 5,300

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Summary of Significant Accounting Policies [Line Items]
Depreciation expense	$ 25,719	$ 23,578
Accrued payment of interest and penalties	99	121
Long-term note receivable	$ 32,440
Notes Receivable Instrument, Interest Rate	4.50%
Notes Receivable Instrument, Maturity Date	Feb. 28, 2023
Interest Receivable	$ 309
Impairment of Intangible Assets, Indefinite-lived	0	0
Deferred revenue recognized	7,116
Revenue, Performance Obligation	21,392
Cash paid, Liabilities	670
Accrued Liabilities	11,048
Revenues	7,307
Air Wisconsin [Member]
Summary of Significant Accounting Policies [Line Items]
Deferred recognizing revenue	43,220
Deferred revenue current	12,500
Deferred Revenue, Noncurrent	30,720
Accounts Receivable, after Allowance for Credit Loss	1,180
Upfront fee	2,504	3,725
Fulfillment costs	$ 269	$ 400

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Property and Equipment Useful lives (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Aircraft [Member]
Property, Plant and Equipment [Line Items]
Property Plant And Equipment Useful Life	7 years
Current Residual Value	$ 50,000
Rotable Parts [Member]
Property, Plant and Equipment [Line Items]
Property Plant And Equipment Useful Life	7 years
Current Residual Value, percent	10.00%
Spare Engines [Member]
Property, Plant and Equipment [Line Items]
Property Plant And Equipment Useful Life	7 years
Current Residual Value	$ 25,000
Ground Equipment [Member]
Property, Plant and Equipment [Line Items]
Current Residual Value, percent	0.00%
Property Plant And Equipment Useful Life	up to 10 years
Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Current Residual Value, percent	0.00%
Property Plant And Equipment Useful Life	up to 10 years
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Current Residual Value, percent	0.00%
Property Plant And Equipment Useful Life	Shorter of asset or lease life

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Summary of ROU assets and lease liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019
Operating Lease, Liability [Abstract]
Right-of-use assets – operating leases	$ 8,582	$ 24,026	$ 70,892
Lease liabilities – operating leases	$ 5,712		$ 40,921

Liquidity - Additional Informat

Liquidity - Additional Information (Detail) $ in Thousands	Oct. 01, 2020Employees	Apr. 13, 2020USD ($)	Mar. 31, 2021USD ($)	Jan. 31, 2021pilots	Jun. 30, 2020BlockHours	Jun. 30, 2020Departures	Jun. 30, 2019	Dec. 31, 2020USD ($)citiesstates	Dec. 31, 2019citiesstates	Apr. 30, 2020USD ($)
Liquidity Uncertainty And Going Concern [Line Items]
Interest rate								4.50%
Maximum [member]
Liquidity Uncertainty And Going Concern [Line Items]
Percentage of Scheduled capacity of passengers								90.00%
Minimum [member]
Liquidity Uncertainty And Going Concern [Line Items]
Percentage of Scheduled capacity of passengers								50.00%
Air Wisconsin [Member]
Liquidity Uncertainty And Going Concern [Line Items]
Number of passenger services in cities | cities								69	81
Number of employees Laid off | Employees	305
Number of passenger services in states | states								28	31
COVID-19 [Member]
Liquidity Uncertainty And Going Concern [Line Items]
Number of block hours operated					1,759	1,271
Percentage increase decrease in the departures operated							86.00%
Percentage increase decrease in the block hours operated							88.00%
Subsequent Event [Member] | Air Wisconsin [Member]
Liquidity Uncertainty And Going Concern [Line Items]
Number of pilots notified that they might be furloughed on April 21, 2021 | pilots				150
Small Business Administration Payroll Protection Program [Member] | Air Wisconsin [Member]
Liquidity Uncertainty And Going Concern [Line Items]
Term Loan Maturity		2 years
Interest rate		1.00%
Aggregate amount due from United Long-term note receivable		$ 10,000
Percentage of the forgiven loan amount that may be used for non payroll costs		40.00%
Treasury Department Payroll Support Program [Member]
Liquidity Uncertainty And Going Concern [Line Items]
Payroll Support Agreement Awardable Amount										$ 42,185
PSP2 Agreement [member] | Subsequent Event [Member] | Air Wisconsin [Member] | Maximum [member]
Liquidity Uncertainty And Going Concern [Line Items]
Proceeds from cares act payroll support program grant			$ 15,536
PSP2 Agreement [member] | Subsequent Event [Member] | Air Wisconsin [Member] | Minimum [member]
Liquidity Uncertainty And Going Concern [Line Items]
Proceeds from cares act payroll support program grant			$ 28,326
CARES Act Payroll Support Program [member] | Air Wisconsin [Member]
Liquidity Uncertainty And Going Concern [Line Items]
Proceeds from cares act payroll support program grant								$ 42,185

Capacity Purchase Agreement w_2

Capacity Purchase Agreement with United - Additional Information (Detail) - United Airlines [Member] - CRJ-200 [Member]	1 Months Ended
	Feb. 28, 2017Aircraft
Extension Period One [Member]
Period of extension of the agreement	2 years
Extension Period Two [Member]
Period of extension of the agreement	2 years
Maximum [member]
Number of aircraft operated	65

Property and Equipment - Summar

Property and Equipment - Summary of aircraft (Detail) - CRJ-200 [Member] - Aircraft	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Owned	64	51
Leased	0	13

Property and Equipment - Additi

Property and Equipment - Additional Information (Detail) $ in Thousands	May 20, 2020USD ($)	Jul. 01, 2019USD ($)Aircraft	Sep. 30, 2020USD ($)	Dec. 31, 2019USD ($)Aircraft	Dec. 31, 2020USD ($)	Sep. 30, 2019USD ($)	Jan. 01, 2019USD ($)
Property, Plant and Equipment [Line Items]
Aggregate purchase price for aircraft acquired	$ 3,000		$ 818
Right-of-use assets				$ 24,026	$ 8,582		$ 70,892
Financing Lease, Lease Receivable				184
Flight Property And Equipment [Member]
Property, Plant and Equipment [Line Items]
Fair market value				15,832
Aircraft lease termination costs				$ 19,539
Descrtption of aircraft engine cycle				on one hundred and forty dollars per remaining engine cycle with a minimum value of $50 per engine, and each of the aircraft airframes was assigned a fair market value of $100.
Right-of-use assets				$ 26,275
Offset by lease liabilities				1,182
Unamortized engine overhauls				$ 9,535
Number of engine acquired | Aircraft				28
Leasehold improvements book value				$ 738
Number of aircraft acquired | Aircraft				14
CRJ-200 [Member] | Bombardier Inc [Member]
Property, Plant and Equipment [Line Items]
Amount paid in installment						$ 25,192
Number of aircraft delivered | Aircraft		14
Remaining installment amount		$ 8,212
Other income				$ 2,537

Income Taxes - Summary of incom

Income Taxes - Summary of income tax provision (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Current Income Tax Expense (Benefit)
Federal	$ (1,061)	$ (247)
State	(80)	(174)
Total Current Benefit	(1,141)	(421)
Deferred Income Tax Expense (Benefit)
Federal	3,646	789
State	(45)	(46)
Total Deferred Expense	3,601	743
Income Tax Expense	$ 2,460	$ 322

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Line Items]
Effective Income Tax Rate, Federal statutory rate	21.00%	21.00%
Valuation allowance release against certain deferred tax assets	$ 6,330	$ 6,330
Estimated effective tax rate applicable to federal net operating losses	21.00%
Estimated effective tax rate applicable to state net operating losses	2.80%
Federal business interest carryforward	$ 0	4,724
Operating loss carryforward valuation allowance	0	6,330
Federal [Member]
Income Tax Disclosure [Line Items]
Net operating losses	27,583	60,940
State [Member]
Income Tax Disclosure [Line Items]
Net operating losses	$ 9,147	$ 17,897

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Effective income tax rate reconciliation
Computed provision for income taxes at the statutory rate	$ 8,867	$ (3,964)
State income tax provision, net of federal income tax benefit	875	(830)
Non-deductible expenses	136	241
Refundable credits as a result of CARES Act	(936)
Valuation allowance changes affecting the provision for income taxes	(6,330)	5,873
Return to provision adjustments	(83)	(954)
Other, net	(69)	(44)
Income Tax Expense	$ 2,460	$ 322

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred Tax Assets
Accruals and reserves not currently deductible	$ 6,129	$ 6,631
Federal NOL and interest expense limitation carryovers	5,803	13,796
State NOL and interest expense limitation carryovers	476	1,106
Accrued and deferred compensation	1,966	2,888
Prepaid items	745	1,198
Lease liability	1,362	4,052
Contract liability	1,982	2,543
Other	657	1,010
Subtotal before valuation allowance	19,120	33,224
Less: valuation allowance	(6,330)	(6,330)
Total Deferred Tax Assets	19,120	26,894
Deferred Tax Liabilities
Property and equipment	(23,268)	(24,696)
Right-of-use asset	(2,046)	(4,791)
Other	(6)	(6)
Total Deferred Tax Liabilities	(25,320)	(29,493)
Net Deferred Income Tax Liabilities	$ (6,200)	$ (2,599)

Income Taxes - Schedule of unre

Income Taxes - Schedule of unrecognized tax benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Unrecognized tax benefits
Unrecognized tax benefits at the beginning of the year	$ 248	$ 388
Gross decreases - lapse of statute	(71)	(140)
Unrecognized tax benefits at the end of the year	177	248
Interest and penalties in year-end balance	$ 99	$ 121

Debt - Schedule Of Long Term De

Debt - Schedule Of Long Term Debt (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Total debt	$ 117,838	$ 120,683
Less: current maturities	23,652	12,845
Long-Term Debt	94,186	107,838
Notes Due December 31, 2025 [Member]
Total debt	80,850	86,497
Credit Agreements Due Through 2022 [Member]
Total debt	26,988	$ 34,186
Paycheck Protection Program Due 2025 [Member]
Total debt	$ 10,000

Debt - Schedule Of Long Term _2

Debt - Schedule Of Long Term Debt (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Apr. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 24, 2018	Feb. 24, 2018	Jan. 25, 2018	Jun. 05, 2017
Long term debt, current portion	$ 23,652		$ 12,845
Promissory Note [Member]
Aggregate principal amount		$ 10,000
Long-term debt, gross		9,106
Long term debt, current portion		$ 894
Credit Agreements Due Through 2022 [Member]
Line of credit				$ 26,987
Aircraft Notes [Member]
Aggregate principal amount	70,000		70,000		$ 70,000	$ 70,000
Future undiscounted interest payments	$ 10,850		$ 16,497		10,850
Credit Agreement [Member] | Credit Agreements Due Through 2022 [Member]
Line of credit								$ 14,397
Line of credit, additional borrowing amount					$ 5,755
Line of credit, maturity date	Dec. 31, 2020
Second Credit Agreement [Member] | Credit Agreements Due Through 2022 [Member]
Line of credit							$ 15,198
Line of credit, additional borrowing amount				$ 6,034
Line of credit, maturity date	Jun. 30, 2022

Debt - Additional information (

Debt - Additional information (Detail) - USD ($) $ in Thousands

Apr. 30, 2019

Dec. 24, 2018

Jun. 30, 2022

Mar. 31, 2022

Dec. 31, 2020

Dec. 31, 2019

Jun. 30, 2019

Jan. 01, 2019

Dec. 31, 2018

Feb. 24, 2018

Jan. 25, 2018

Jun. 05, 2017

Jul. 31, 2003

Interest rate

4.50%

Line of credit, payment

$ 3,963

Operating lease right of use asset

$ 8,582

$ 24,026

$ 70,892

Hangar [Member]

Operating lease right of use asset

3,010

Third Amendment Credit Agreement [Member] | Two Thousand Twenty July One to Two Thousand Twenty One December Thirty One [Member]

Debt instrument, periodic payment, principal

7,273

Aircraft Notes [Member]

Interest rate

4.00%

Aggregate principal amount

$ 70,000

70,000

70,000

$ 70,000

Mandatory semi-annual amortization commencing on June 30, 2021

3,500

Future undiscounted interest payments

10,850

$ 10,850

$ 16,497

Credit Agreements Due Through 2022 [Member]

Interest rate

5.00%

5.00%

Line of credit

$ 26,987

Credit Agreements Due Through 2022 [Member] | Second Credit Agreement [Member]

Line of credit

$ 15,198

Line of credit, additional borrowing amount

$ 6,034

Line of credit, payment extended

$ 7,273

$ 7,925

Line of credit, maturity date

Jun. 30, 2022

Credit Agreements Due Through 2022 [Member] | Credit Agreement [Member]

Line of credit

$ 14,397

Line of credit, additional borrowing amount

$ 5,755

Line of credit, payment

$ 7,198

Line of credit, maturity date

Dec. 31, 2020

Credit Agreements Due Through 2022 [Member] | Forecast [Member] | Second Credit Agreement [Member]

Line of credit, payment

$ 3,963

City of Milwaukee, Wisconsin variable rate Industrial Development Bonds [Member]

Aggregate principal amount

$ 4,275

Debt - Schedule of Maturities o

Debt - Schedule of Maturities of Long-term Debt (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Maturities of Long-term Debt [Abstract]
2021	$ 23,652
2022	26,110
2023	11,897
2024	11,644
2025	44,535
Total	$ 117,838	$ 120,683

Lease Obligations - Additional

Lease Obligations - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019
Lessee, Lease, Description [Line Items]
Operating lease right of use asset	$ 8,582	$ 24,026	$ 70,892
Current portion of operating lease liability	1,361	6,311
Long-term operating lease liability	4,351	10,538
Cash payments included in the measurement of lease liabilities related to operating leases	5,398	29,502
Operating lease rent expense	$ 11,293	$ 51,490
Minimum [Member]
Lessee, Lease, Description [Line Items]
Lease term of training simulators	12 months
Operating Lease Remaining Lease	20 months
Maximum [Member]
Lessee, Lease, Description [Line Items]
Operating Lease Remaining Lease	13 years

Lease Obligations - Summary Of

Lease Obligations - Summary Of Weighted average Terms and Discount Rate For Operating Leases (Detail)	Dec. 31, 2020
Leases [Abstract]
Weighted-average remaining lease term	4 years 11 months 8 days
Weighted-average discount rate	6.99%

Lease Obligations - Schedule of

Lease Obligations - Schedule of Component Of Lease Cost (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Lease, Cost [Abstract]
Operating lease cost	$ 9,326	$ 27,624
Short-term lease cost	1,662	4,331
Variable lease cost	(994)	182
Lease termination expense	1,299	19,353
Total Lease Cost	$ 11,293	$ 51,490

Lease Obligations - Schedule _2

Lease Obligations - Schedule of Future Minimum Lease Payments Under Non-Cancelable Operating Leases (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Jan. 01, 2019
Leases [Abstract]
2021	$ 1,766
2022	1,778
2023	1,513
2024	1,103
2025	390
Thereafter	579
Operating lease obligations, Total	7,129
Less imputed interest	(1,417)
Total Lease Liabilities	$ 5,712	$ 40,921

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Thousands	Jun. 30, 2021USD ($)	Dec. 31, 2020USD ($)Letter_Of_Credit
Other Commitments [Line Items]
Number of outstanding letters of credit | Letter_Of_Credit		5
Air Wisconsin [Member]
Other Commitments [Line Items]
Outstanding letters of credit facility		$ 810
Aircraft Notes principal [Member]
Other Commitments [Line Items]
Prinipal amount of notes payable	$ 3,500
Letter of Credit [Member]
Other Commitments [Line Items]
Outstanding letters of credit facility		$ 348

Commitments and Contingencies_2

Commitments and Contingencies - Cash Obligations (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Contractual Obligation Fiscal Year Maturity [Line Items]
Long-term debt, Total	$ 117,838	$ 120,683
Long-term debt, due in 2021	23,652
Long-term debt, due in 2022	26,110
Long-term debt, due in 2023	11,897
Long-term debt, due in 2024	11,644
Long-term debt, due in 2025	44,535
Operating lease obligations, Total	7,129
Operating lease obligations, due in 2021	1,766
Operating lease obligations, due in 2022	1,778
Operating lease obligations, due in 2023	1,513
Operating lease obligations, due in 2024	1,103
Operating lease obligations, due in 2025	390
Operating lease obligations, due Thereafter	579
Total cash obligations	126,820
Total cash obligations, due in 2021	26,680
Total cash obligations, due in 2022	28,266
Total cash obligations, due in 2023	13,461
Total cash obligations, due in 2024	12,771
Total cash obligations, due in 2025	45,063
Total cash obligations, due Thereafter	579
Aircraft Notes principal [Member]
Contractual Obligation Fiscal Year Maturity [Line Items]
Long-term debt, Total	70,000
Long-term debt, due in 2021	7,000
Long-term debt, due in 2022	7,000
Long-term debt, due in 2023	7,000
Long-term debt, due in 2024	7,000
Long-term debt, due in 2025	42,000
Aircraft Notes interest [Member]
Contractual Obligation Fiscal Year Maturity [Line Items]
Long-term debt, Total	10,850
Long-term debt, due in 2021	2,730
Long-term debt, due in 2022	2,450
Long-term debt, due in 2023	2,170
Long-term debt, due in 2024	1,890
Long-term debt, due in 2025	1,610
Other Loans principal [Member]
Contractual Obligation Fiscal Year Maturity [Line Items]
Long-term debt, Total	36,988
Long-term debt, due in 2021	13,922
Long-term debt, due in 2022	16,660
Long-term debt, due in 2023	2,727
Long-term debt, due in 2024	2,754
Long-term debt, due in 2025	925
Other Loans interest [Member]
Contractual Obligation Fiscal Year Maturity [Line Items]
Long-term debt, Total	1,853
Long-term debt, due in 2021	1,262
Long-term debt, due in 2022	378
Long-term debt, due in 2023	51
Long-term debt, due in 2024	24
Long-term debt, due in 2025	$ 138

Retirement Plans - Additional I

Retirement Plans - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Retirement Benefits [Abstract]
Total expense under defined contribution retirement plans	$ 3,764	$ 4,467

Related-Party Transactions - Ad

Related-Party Transactions - Additional Information (Detail) $ / shares in Units, $ in Thousands

Dec. 31, 2020

Dec. 30, 2020USD ($)

Sep. 30, 2020

Sep. 29, 2020USD ($)

Jul. 01, 2020

Jun. 30, 2020USD ($)

Apr. 20, 2020

Apr. 15, 2020USD ($)

Jan. 31, 2020USD ($)$ / sharesshares

Dec. 31, 2020USD ($)

Dec. 31, 2019USD ($)

Jan. 17, 2020Aircraft

Related Party Transaction [Line Items]

Payments to related parties pursuant to certain aircraft and engines leases and for other professional services

$ 390

$ 3,979

Operating lease agreements term

April 2010 through January 2020

Series C Redeemable Convertible Preferred Stock [Member]

Related Party Transaction [Line Items]

Common stock issuable upon conversion of temporary equity | shares

16,500,000

Dividend declared

$ 198

$ 198

$ 198

$ 165

Date of dividend declaration

Dec. 30, 2020

Sep. 29, 2020

Jun. 30, 2020

Apr. 15, 2020

Date of dividend payment

Dec. 31, 2020

Sep. 30, 2020

Jul. 1, 2020

Apr. 20, 2020

Convesrion price, preferred stock | $ / shares

$ 0.15091

Southshore [Member] | CRJ-200 [Member]

Related Party Transaction [Line Items]

Number Of Flights Acquired | Aircraft

3

Business acquistion liabilites assumed

$ 3,466

Southshore [Member] | CRJ-200 [Member] | Series C Redeemable Convertible Preferred Stock [Member]

Related Party Transaction [Line Items]

Business acquisition shares issued or issuable | shares

4,000

Business acquisition shares issued or issuable value

$ 13,200

Business acquisiton shares | $ / shares

$ 3.30

Air Wisconsin [Member]

Related Party Transaction [Line Items]

Payments to related parties pursuant to certain aircraft and engines leases and for other professional services

$ 150

3,739

AWAC Aviation Inc [Member] | Financial Advisory And Management Services [Member]

Related Party Transaction [Line Items]

Monthly recurring fee payable pursuant to service agreement

20

Payment For Management services fee

240

240

Aircraft [Member] | Air Wisconsin [Member]

Related Party Transaction [Line Items]

Payments to related parties pursuant to certain aircraft and engines leases and for other professional services

66

1,878

Engines To Support Aircraft Fleet [Member] | Air Wisconsin [Member]

Related Party Transaction [Line Items]

Payments to related parties pursuant to certain aircraft and engines leases and for other professional services

$ 84

1,661

Airframe [Member]

Related Party Transaction [Line Items]

Related party transaction purchases of previously leased airframes

$ 200

Earnings Per Share and Equity -

Earnings Per Share and Equity - Calculations of Net Income Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Net income (loss)	$ 39,763	$ (19,214)
Preferred stock dividends	759
Net income (loss) applicable to common stockholders	$ 39,004	$ (19,214)
Weighted average common shares outstanding
Shares used in calculating basic earnings per share	54,863	54,863
Stock options	559
Series C Preferred	15,777
Shares used in calculating diluted earnings per share	71,199	54,863
Earnings (loss) allocated to common stockholders per common share
Basic	$ 0.71	$ (0.35)
Diluted	$ 0.56	$ (0.35)

Earnings Per Share and Equity_2

Earnings Per Share and Equity - Additional Information (Detail) $ / shares in Units, $ in Thousands

Dec. 31, 2023

Dec. 31, 2022USD ($)$ / shares

Jan. 07, 2021$ / sharesshares

Dec. 31, 2020shares

Dec. 30, 2020USD ($)

Sep. 30, 2020

Sep. 29, 2020USD ($)

Jul. 01, 2020

Jun. 30, 2020USD ($)

Apr. 20, 2020

Apr. 15, 2020USD ($)

Jan. 31, 2020USD ($)shares

Dec. 31, 2020shares

Class of Stock [Line Items]

Preferred stock, liquidation preference | $ / shares

$ 0.80

Common Stock [Member]

Class of Stock [Line Items]

Convertible preferred stock, shares issued upon conversion

16,500,000

16,500,000

Reporting Adjustment Period [Member]

Class of Stock [Line Items]

Outstanding shares are traded on reporting period, percentage

5.00%

Commencing trading date of company outstanding shares

August 28, 2020

Subsequent Event [Member]

Class of Stock [Line Items]

Common stock, convertible, conversion price | $ / shares

$ 0.15091

Subsequent Event [Member] | Common Stock [Member]

Class of Stock [Line Items]

Convertible preferred stock, shares issued upon conversion

16,500,000

Series C Redeemable Convertible Preferred Stock [Member]

Class of Stock [Line Items]

Temporary equity stock issued during the period shares new issues

4,000,000

4,000,000

Dividend rate

6.00%

Dividend declared | $

$ 198

$ 198

$ 198

$ 165

Date of dividend declaration

Dec. 30, 2020

Sep. 29, 2020

Jun. 30, 2020

Apr. 15, 2020

Date of dividend payment

Dec. 31, 2020

Sep. 30, 2020

Jul. 1, 2020

Apr. 20, 2020

Series C Preferred Stock [Member]

Class of Stock [Line Items]

Minimum percentage of shares issued to outstanding stock

5.00%

Preferred stock, redemption date

Dec. 31, 2024

Series C Preferred Stock [Member] | Southshore [Member] | Investors' Rights Agreement [Member]

Class of Stock [Line Items]

Share requisition period after complying with reporting requirements

180

Shares issued upon conversion of preferred shares, percentage of outstanding stock maximum

40.00%

Minimum anticipated aggregate offering price, net of selling expenses | $

$ 10,000

Series C Preferred Stock [Member] | Minimum [Member]

Class of Stock [Line Items]

Preferred stock, shares outstanding

800

Series C Preferred Stock [Member] | Forecast [Member]

Class of Stock [Line Items]

Percentage of increase in preferential dividends

1.00%

Preferred stock, convertible, threshold trading days

90

Preferred stock, convertible, threshold calendar day

45

Conversion of preferred stock, maximum amount converted | $

$ 16,500

Cumulative quarterly preferred stock dividend rate percentage

0.50%

Series C Preferred Stock [Member] | Subsequent Event [Member]

Class of Stock [Line Items]

Percentage of diluted shares of capital stock

23.10%

Stock Options - Additional Info

Stock Options - Additional Information (Detail) - 2015 Stock Option [Member] - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted		558,835
Stock option issued, exercise price		$ 0.21386
Value of the option at the date of grant	$ 0.07
Options granted, life	7 years
Options granted, risk free interest rate	2.01%
Options granted, expected volatility	157.10%

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Cash payments for interest	$ 7,311	$ 1,841
Cash payments for income taxes	(1,035)	39
Cash payments included in the measurement of lease liabilities related to operating leases	$ 5,398	29,502
Fair market value aircraft acquired in a non-cash lease termination transaction		$ 15,832

Intangible Assets - Components

Intangible Assets - Components of Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Trade names and air carrier certificate	$ 5,300	$ 5,300
Total	$ 5,300	$ 5,300

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 30, 2021	Mar. 31, 2021
Subsequent Event [Line Items]
Increase in repurchase of common stock, per month	$ 1,000
Subsequent Event [Member] | Common Stock [Member]
Subsequent Event [Line Items]
Future stock repurchase program adopted, value		$ 1,000