Harbor Diversified (HRBR) 10-K 31 Mar 22 2021 FY Annual report Financial data

Cover

Cover - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Mar. 18, 2022	Jun. 30, 2021
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, 2021
Document Fiscal Year Focus	2021
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		47,155,297
Entity Public Float			$ 64.3
ICFR Auditor Attestation Flag	false
Auditor Name	GRANT THORNTON LLP
Auditor Firm ID	248
Auditor Location	Milwaukee, Wisconsin

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current Assets
Cash and cash equivalents	$ 37,170	$ 130,373
Restricted cash	1,449	820
Marketable securities	138,370	0
Accounts receivable, less allowances of $40 as of December 31, 2021 and $59 as of December 31, 2020	7,422	7,977
Spare parts and supplies, less allowances of $10,819 as of December 31, 2021 and $9,649 as of December 31, 2020	5,200	5,937
Contract costs	518	433
Prepaid expenses and other	4,174	2,310
Total Current Assets	194,303	147,850
Property and Equipment
Flight property and equipment	259,720	258,981
Ground property and equipment	8,252	8,127
Less accumulated depreciation and amortization	(143,313)	(117,717)
Net Property and Equipment	124,659	149,391
Other Assets
Operating lease right-of-use asset	18,679	8,582
Intangibles	5,300	5,300
Long-term deferred tax asset	533	0
Long-term investments	4,275	4,275
Long-term contract costs	96	566
Long-term notes receivable	47,568	32,440
Other	3,988	2,049
Total Other Assets	80,439	53,212
Total Assets	399,401	350,453
Current Liabilities
Accounts payable	20,060	11,773
Accrued payroll and employee benefits	14,885	14,761
Current portion of operating lease liability	5,150	1,361
Other accrued expenses	172	345
Contract liabilities	43,890	18,443
Income taxes payable		107
Current portion of long-term debt (stated principal amount of $3,500 as of December 31, 2021 and $20,922 as of December 31, 2020)	5,880	23,652
Total Current Liabilities	90,037	70,442
Other Liabilities
Long-term debt (stated principal amount of $56,000 as of December 31, 2021 and $86,066 as of December 31, 2020)	61,670	94,186
Long-term promissory note	4,275	4,275
Deferred tax liability	688	6,200
Long-term operating lease liability	10,877	4,351
Long-term contract liabilities	1,326	7,780
Deferred revenue, net of current portion	9,046	30,720
Other	2,722	2,774
Total Long-Term Liabilities	90,604	150,286
Commitments and Contingencies (Note 8)
Series C Convertible Redeemable Preferred Stock, $0.01 par value, 4,000,000 shares authorized, issued and outstanding at December 31, 2021 and December 31, 2020	13,200	13,200
Stockholders' Equity
Common Stock, $0.01 par value, 100,000,000 shares authorized, 55,481,140 shares issued at December 31, 2021 and December 31, 2020, 53,316,299 shares outstanding at December 31, 2021 and 54,863,305 shares outstanding at December 31, 2020	555	555
Additional paid-in capital	287,429	288,221
Retained deficit	(79,144)	(171,770)
Treasury stock	(3,280)	(481)
Total Stockholders' Equity	205,560	116,525
Total Liabilities and Stockholders' Equity	$ 399,401	$ 350,453

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Allowance for doubtful accounts receivables	$ 40	$ 59
Inventory allowances valuation reserves	10,819	9,649
Current portion of long-term debt principal amount	3,500	20,922
Non-current portion of long term debt principal amount	$ 56,000	$ 86,066
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	53,316,299	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	4,000,000
Temporary equity shares issued	4,000,000	4,000,000
Temporary equity shares outstanding	4,000,000	4,000,000

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating Revenues
Total Operating Revenues	$ 247,579	$ 185,949
Operating Expenses
Payroll and related costs	106,881	99,100
Aircraft fuel and oil	171	55
Aircraft maintenance, materials and repairs	43,742	27,350
Aircraft rent	67	6,713
Other rents	5,375	4,580
Depreciation, amortization and obsolescence	26,552	27,222
Purchased services and other	25,938	19,764
Payroll Support Program	(66,316)	(42,185)
Total Operating Expenses	142,410	142,599
Income From Operations	105,169	43,350
Other Income (Expense)
Interest income	2,024	628
Interest expense	(847)	(1,736)
Loss on marketable securities	(1,158)	0
Gain on extinguishment of debt	10,363	0
Other, net	2,496	(19)
Total Other Income (Expense)	12,878	(1,127)
Net Income Before Taxes	118,047	42,223
Income Tax Expense	25,421	2,460
Net Income	92,626	39,763
Preferred Stock Dividends	792	759
Net Income available to Common Stockholders	$ 91,834	$ 39,004
Basic earnings per share	$ 1.69	$ 0.71
Diluted earnings per share	$ 1.29	$ 0.56
Weighted average common shares:
Basic	54,321	54,863
Diluted	71,249	71,199
Contract Revenues [Member]
Operating Revenues
Total Operating Revenues	$ 247,519	$ 185,866
Contract Service and Other [Member]
Operating Revenues
Total Operating Revenues	$ 60	$ 83

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Repurchased Stock [Member]	Preferred Stock [Member]Mezzanine Equity Series C Convertible Redeemable Preferred Stock [Member]
Beginning Balance at Dec. 31, 2019	$ 77,521	$ 555	$ 288,980	$ (211,533)	$ (481)	$ 0
Beginning balance, Shares at Dec. 31, 2019		54,863			618	0
Net income	39,763			39,763
Dividend	(759)		(759)
Preferred Stock						$ 13,200
Preferred Stock, Shares						4,000
Ending Balance at Dec. 31, 2020	116,525	$ 555	288,221	(171,770)	$ (481)	$ 13,200
Ending balance, shares at Dec. 31, 2020		54,863			618	4,000
Net income	92,626			92,626
Dividend	(792)		(792)
Repurchased stock	(2,799)				$ (2,799)
Repurchased stock ,Shares		(1,547)			1,547
Ending Balance at Dec. 31, 2021	$ 205,560	$ 555	$ 287,429	$ (79,144)	$ (3,280)	$ 13,200
Ending balance, shares at Dec. 31, 2021		53,316			2,165	4,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash Flows From Operating Activities
Net income	$ 92,626	$ 39,763
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and obsolescence allowance	26,552	27,222
Aircraft lease termination costs	0	1,263
Amortization of contract costs	(3,593)	(2,502)
Amortization of engine overhauls	1,901	1,265
Deferred income taxes	(6,045)	3,601
(Gain) loss on disposition of property and equipment	(298)	648
Loss on marketable securities	1,158	0
Gain on extinguishment of debt	(10,363)	0
Changes in operating assets and liabilities:
Accounts receivable	2,294	(2,444)
Notes Receivable	(15,128)	(32,440)
Spare parts and supplies	(433)	622
Prepaid expenses and other	(3,803)	(1,885)
Operating lease right-of-use asset	218	2,520
Accounts payable	8,287	(7,790)
Accrued payroll and employee benefits	124	(713)
Other accrued expenses	(173)	18
Long-term deferred revenue	(21,674)	30,720
Contract liabilities	22,586	12,297
Income taxes payable	(107)	(106)
Other long-term liabilities	84	1,119
Net Cash Provided by Operating Activities	94,213	73,178
Cash Flows From Investing Activities
Additions to property and equipment	(3,637)	(8,749)
Proceeds on disposition of property and equipment	30	95
Purchase of marketable securities	(267,157)
Sale of marketable securities	127,629	0
Net Cash Used in Investing Activities	(143,135)	(8,654)
Cash Flows From Financing Activities
Repayments of long-term debt	(40,061)	(12,845)
Proceeds from note payable	0	10,000
Dividends paid	(792)	(759)
Repurchase of common stock	(2,799)	0
Net Cash Used in Financing Activities	(43,652)	(3,604)
(Decrease) Increase in Cash, Cash Equivalents and Restricted Cash	(92,574)	60,920
Cash, Cash Equivalents and Restricted Cash, beginning of year	131,193	70,273
Cash, Cash Equivalents and Restricted Cash, end of year	$ 38,619	$ 131,193

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
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. (Harbor) and subsidiaries (collectively, the Company). Harbor 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 regional air services 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 (United capacity purchase agreement) with United Airlines, Inc. (United) that was entered into in February 2017 and amended in October 2020 and April 2021. United is currently Air Wisconsin’s sole airline partner. For additional information, refer to Note 3, Capacity Purchase Agreement with United. Air Wisconsin operates as a United Express carrier with a 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 revenues in 2021 and 2020 were derived from operations associated with United. Contract Revenues The Company recognizes revenue under the United capacity purchase agreement over time as services are provided. United pays Air Wisconsin 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 incentive payments available, and penalties payable, primarily based on flight completion, on-time United makes provisional cash payments to Air Wisconsin during each month of service based on projected flight schedules. These provisional cash payments are subsequently reconciled with United based on actual completed flight activity. As of the date of this filing, these payments are reconciled through October 2021. As of December 31, 2021, Air Wisconsin owed United $922, which is recorded in contract liabilities, on the consolidated balance sheets. Under the United capacity purchase agreement, Air Wisconsin is also eligible to receive incentive payments, or may be required to pay penalties, upon the achievement of, or failure to achieve, certain performance criteria. The incentives are defined in the agreement and performance is measured on a monthly basis. At the end of each month during the term of the agreement, Air Wisconsin calculates the incentives achieved, or penalties payable, during that period and recognizes revenue accordingly, subject to the variable constraint guidance under Financial Accounting Standards Board (FASB) Accounting Standards Update (ASU) No. 606, Revenue from Contracts with Customers November and December, 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. Air Wisconsin deferred fixed revenues between April 2020 and June 2021 due to the significant decrease in its completed flights as a result of the COVID-19 Consistent with the analysis above, for the year ended December 31, 2021, as compared to the year ended December 31, 2020, Air Wisconsin also recognized increased non-refundable As part of the CPA Amendment, United issued a note receivable to Air Wisconsin in the amount of $11,048 along with a cash settlement of $670, of which $4,410 was deferred as of December 31, 2020, with the remaining portion to be recognized in proportion to the number of flights expected to be completed in subsequent periods. For the year ended December 31, 2021, Air Wisconsin recorded $1,702 of revenue related to these items, compared to $7,307 of revenue related to these items for the year ended December 31, 2020. In October 2021, in accordance with the CPA Amendment, Air Wisconsin received $294 from United for the opening of a crew base and recognized revenue of $207 using a cumulative catchup adjustment based on prior and future expected departures. In total, Air Wisconsin recognized revenue of $222 and deferred the remaining portion which will be recognized in proportion to the number of flights expected to be completed in subsequent periods. The current portion of the deferred CPA Amendment revenue, in the amount of $2,348, is recorded as part of contract liabilities, and the long-term portion of the deferred CPA Amendment revenue, in the amount of $434, is recorded as long-term contract liabilities on the consolidated balance sheets. The timing of the recognition of deferred fixed revenues, non-refundable The amount of revenues recognized for the year s The CPA Amendment provided, among other things, 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 resulting from the COVID-19 Other Revenues Other revenues primarily consist of the sales of parts to other airlines and are immaterial in all periods presented. The transaction price for the sale of these parts generally is fair market value. Cash and Cash Equivalents Money market funds and investments and deposits with an original maturity of three months or less when acquired are considered cash and cash equivalents. Restricted Cash As of December 31, 2021, the Company had a restricted cash balance of $1,449. A portion of the balance secures a credit facility for the issuance of letters of credit guaranteeing the performance of Air Wisconsin’s obligations under certain lease agreements, airport agreements and insurance policies. The remaining portion is cash held for the repurchase of shares under Harbor’s stock repurchase program. For additional information, refer to Note 8, Commitments and Contingencies Stock Repurchase Program. Marketable Securities The Company’s equity security investments, consisting of exchange-traded funds and mutual funds, are recorded at fair value based on quoted market prices (level 1) in marketable securities on the consolidated balance sheets, in accordance with the guidance in ASC Topic 321, Investments-Equity Securities The calculation of net unrealized gains and losses that relate to marketable securities held as of December 31, 2021 is as follows: Net losses recognized during the period on equity securities $ (1,158 ) Less: Net gains recognized during the period on equity securities sold during the period 2 Unrealized losses recognized during the period on equity securities held as of December 31, 2021 $ (1,160 ) 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 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 Rotable parts 7 years 10% Spare engines 7 years $ 25 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 visit. Lotus’ engine maintenance costs are expensed. Depreciation expense in 2021 and 2020 was $24,997 and $25,719, 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 required to be performed as of December 31, 2021 and 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, 2021 and 2020. Maintenance The Company operates its aircraft under a continuous inspection and maintenance program. Generally, the normal cost of recurring maintenance is expensed when incurred. However, we use the deferral method of accounting for Air Wisconsin’s planned major maintenance activities for engines pursuant to which the capitalized engine overhaul costs are amortized over the estimated useful life measured in engine cycles remaining until the next scheduled shop visit. 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 2018. With a few exceptions, the Company is no longer subject to state or local income tax examinations for years prior to 2017. As of December 31, 2021, 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 accrued $57 and $99 for the payment of interest and penalties at December 31, 2021 and 2020, respectively . Comprehensive Income The Company does not have any components of comprehensive income and, as of December 31, 2021 and 2020, 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 United is currently Air Wisconsin’s sole airline partner. Substantially all the Company’s revenues in the years ended December 31, 2021 and 2020 were derived from the United capacity purchase agreement. For additional information, refer to Note 3, Capacity Purchase Agreement with United 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, particularly in light of the impact of the COVID-19 Fair Value of Financial Instruments The Company’s financial instruments include cash and cash equivalents, restricted cash, marketable securities, accounts receivable, long-term investments, accounts payable, and long-term debt. The Company believes the carrying amounts of these financial instruments, with the exception of marketable securities, 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. Marketable securities are reported at fair value based on quoted market prices. 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). Fair Value Measurement 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. The table below sets forth the Company’s classification of marketable securities and long-term investments as of: December 31, 2021 Total Level 1 Level 2 Level 3 Marketable securities – exchange-traded funds $ 113,936 $ 113,936 $ — $ — Marketable securities –mutual funds 24,434 24,434 Long-term investments – bonds (see Note 6) 4,275 — 4,275 — Total $ 142,645 $ 138,370 $ 4,275 $ — December 31, 2020 Total Level 1 Level 2 Level 3 Long-term investments – bonds (see Note 6) $ 4,275 $ — $ 4,275 $ — Total $ 4,275 $ — $ 4,275 $ — Recently Adopted Accounting Pronouncements In August 2020, FASB issued ASU No. 2020-06, Debt (Subtopic 470-20); 815-40) 2020-06). 2020-06 2020-06 In August 2018, FASB issued ASU 2018-13, Value Measurements Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement. 2018-13 2018-13 2018-13 Upcoming Accounting Pronouncement In June 2016, FASB issued ASU 2016-13, Financial Instruments—Credit Losses Measurement of Credit Losses on Financial Instruments 2016-13). 2016-13 2016-13 2016-13

Liquidity

Liquidity	12 Months Ended
	Dec. 31, 2021
Text Block [Abstract]
Liquidity and Management's Plan, COVID-19	2. Liquidity The Company’s ability to meet its liquidity needs is dependent upon its cash, cash equivalents and marketable securities balances and its ability to generate 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. The Company currently believes its available working capital and anticipated cash flows from operations will be sufficient to meet the Company’s liquidity requirements for at least the next 12 months from the date of this filing. However, there can be no assurance that the Company will be able to generate sufficient cash flows from operations, or that additional funds will be available, to meet its future liquidity needs. Impact of the COVID-19 As of the date of this filing, there continue to be widespread concerns regarding the ongoing impacts and disruptions caused by the COVID-19 COVID-19 COVID-19 COVID-19 Reduction in Demand for Air Travel Public concerns about the COVID-19 COVID-19 pre-pandemic United Capacity Purchase Agreement Since a portion of the Company’s revenues is fixed due to the structure of the United capacity purchase agreement, the impact of the COVID-19 COVID-19 Summary of Significant Accounting Policies Paycheck Protection Program Air Wisconsin’s receipt of governmental assistance has mitigated to some extent the adverse impacts of the COVID-19 In April 2020, Air Wisconsin received a $10,000 loan (SBA Loan) under the small business Paycheck Protection Program (PPP) established under the Coronavirus Aid, Relief, and Economic Security Act (CARES Act) and administered by the Small Business Administration (SBA). The application for this loan 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 bore interest at a rate of 1.0% per annum. Under the CARES Act, Air Wisconsin applied for forgiveness of the SBA Loan, and the SBA granted forgiveness of all principal and accrued interest on the SBA Loan in August 2021 in the amount of $10,135, which was recorded as gain on extinguishment of debt in the consolidated statements of operations for the year ended December 31, 2021 included within this Annual Report. Payroll Support Program In April 2020, Air Wisconsin entered into a Payroll Support Program Agreement (PSP-1 PSP-1 In December 2020, the federal Consolidated Appropriations Act of 2021 (PSP Extension Law) was adopted, which provided 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 with the Treasury (the PSP-2 PSP-1 PSP-2 In March 2021, the federal American Rescue Plan Act of 2021 (American Rescue Plan) was adopted, which provided further payroll support to eligible air carriers. In June 2021, pursuant to the American Rescue Plan, Air Wisconsin entered into a Payroll Support Program 3 Agreement with the Treasury (the PSP-3 PSP-1 PSP-2 PSP-1 PSP-2 PSP-3 The PSP Agreements contain various covenants, including that (i) the payroll support proceeds must be used exclusively for the payment of wages, salaries and benefits, (ii) Air Wisconsin cannot involuntarily terminate or furlough any employee or reduce any employee’s pay rates or benefits without that employee’s consent, in any case prior to certain dates, (iii) Air Wisconsin cannot pay total compensation to certain employees in excess of certain total compensation caps, (iv) Air Wisconsin cannot pay dividends or make other capital distributions prior to certain dates, and (v) neither Air Wisconsin nor any of its affiliates can purchase an equity security of Air Wisconsin or any direct or indirect parent company of Air Wisconsin that is listed on a national securities exchange prior to certain dates. If Air Wisconsin fails to comply with its obligations under these agreements, it may be required to repay some or all of the funds provided to it under the PSP Agreements. Any such default, acceleration, insolvency or failure to comply would likely have a material adverse effect on the Company’s business. The Treasury commenced a routine audit of Air Wisconsin’s compliance with the terms of the PSP-1 PSP-2 PSP-3 Commitments and Contingencies The proceeds of the Treasury Payroll Support under the PSP Agreements are recorded in cash and cash equivalents when received and are recognized as a contra-expense under Payroll Support Program in the consolidated statements of operations over the periods for which the funds are intended to offset payroll expenses. In the year ended December 31, 2021, Air Wisconsin received approximately $66,316 under the Payroll Support Program. The Company recognized approximately $66,316 and $42,185 s and 2020, respectively.

Capacity Purchase Agreement wit

Capacity Purchase Agreement with United	12 Months Ended
	Dec. 31, 2021
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 to operate up to 65 CRJ-200 February 2023

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Property and Equipment	4. Property and Equipment As of December 31, 2021, Air Wisconsin owned 64 CRJ-200 In January 2020, Harbor 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 Related-Party Transactions 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, 2021
Income Tax Disclosure [Abstract]
Income Taxes	5. Income Taxes The income tax provision consists of the following: Year ended December 31, 2021 2020 Current Expense (Benefit) Federal $ 27,084 $ (1,061 ) State 4,382 (80 ) Total Current Expense (Benefit) 31,466 (1,141 ) Deferred (Benefit) Expense Federal (5,405 ) 3,646 State (640 ) (45 ) Total Deferred (Benefit) Expense (6,045 ) 3,601 Income Tax Expense $ 25,421 $ 2,460 The following is a reconciliation between a federal income tax rate of 21% and the effective tax rate which is derived by dividing the provision for income taxes by the income before the provision for income taxes: Year ended December 31, 2021 2020 Computed provision for income taxes at the statutory rate $ 24,790 $ 8,867 Increase (decrease) in income taxes resulting from: State income tax provision, net of federal income tax benefit 2,757 875 Non-deductible 52 136 Tax exempt income (2,100 ) — Refundable credits as a result of CARES Act — (936 ) Valuation allowance changes affecting the provision for income taxes — (6,330 ) Return to provision adjustments — (83 ) Other, net (78 ) (69 ) Provision for income taxes $ 25,421 $ 2,460 As of December 31, 2021, the Company’s deferred tax assets were primarily the result of deferred revenues which have previously been included in taxable income. For the year ended December 31, 2020, the Company recorded a net valuation allowance release of $6,330, comprising a full valuation allowance 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, 2021 and 2020, the Company achieved three years of cumulative pretax income. In addition, the projection of taxable income in future periods 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. Therefore, no valuation allowance is necessary as of December 31, 2021. 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, 2021 2020 Deferred Tax Assets Accruals and reserves not currently deductible $ 5,647 $ 6,129 Federal NOL and interest expense limitation carryovers — 5,803 State NOL and interest expense limitation carryovers 21 476 Accrued and deferred compensation 2,562 1,966 Prepaid items 891 745 Lease liability 1,033 1,362 December 31, 2021 2020 Contract liability 1,215 1,982 Deferred revenues 11,328 — Unrealized loss on investments 276 — Other 1,266 657 Total Deferred Tax Assets 24,239 19,120 Deferred Tax Liabilities Property and equipment (22,607 ) (23,268 ) Right-of-use (1,663 ) (2,046 ) Other (124 ) (6 ) Total Deferred Tax Liabilities (24,394 ) (25,320 ) Net Deferred Income Tax Liabilities $ (155 ) $ (6,200 ) At December 31, 2021 and 2020, the Company had federal net operating losses of approximately $0 and $27,583, respectively, and state net operating losses of approximately $731 and $9,147, respectively. As of December 31, 2021, the estimated effective tax rate applicable to the federal and state net operating losses are 21.0% and .05%, 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. The Company has no ongoing federal or state examinations. Federal tax years 2018, 2019, and 2020 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, 2021 and 2020 is as follows: December 31, 2021 2020 Unrecognized tax benefits at the beginning of the year $ 177 $ 248 Gross decreases – lapse of statute (59 ) (71 ) Unrecognized tax benefits at the end of the year $ 118 $ 177 Interest and penalties in year-end $ 57 $ 99

Debt

Debt	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Debt	6. Debt Long-Term Debt Long-term debt consists of the following (with interest rates, as of December 31, 2021 and December 31, 2020): December 31, 2021 2020 Notes, due December 31, 2025, 4.0% (a) $ 67,550 $ 80,850 Credit Agreements, due through 2022, 5.0% (b) — 26,988 SBA Loan, due 2025, 1.0% (c) — 10,000 Total debt 67,550 117,838 Less: current maturities 5,880 23,652 Long-Term Debt $ 61,670 $ 94,186 (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 maturity date was extended to December 31, 2025. The aggregate principal amount of the senior aircraft notes in excess of $70,000, the entire outstanding principal balance of the subordinated aircraft notes and all accrued interest 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, 2021 and 2020, the future undiscounted interest payments that were capitalized as part of the debt were $8,050 and $10,850, respectively. 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. The Aircraft Notes are secured by Air Wisconsin’s owned aircraft and certain spare engines and spare parts. The carrying amount of the collateral exceeds the value of the debt. (b) Air Wisconsin entered into a credit agreement with the Lender in June 2017 and a second credit agreement in January 2018, both of which were subsequently amended in December 2018 and again in June 2019 for additional funding and to extend the maturity date. The loans made by the Lender under these two credit agreements (Other Loans) had maturity dates of December 31, 2020 and June 30, 2022, respectively. The loans outstanding under the 2017 credit agreement were paid in full in 2020, and the loans outstanding under the 2018 credit agreement were paid in full in 2021. (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 and accrued interest were forgiven in August 2021. The forgiveness resulted in a $10,135 gain on extinguishment of debt. For additional information, refer to Note 2, Liquidity In June 2021, Air Wisconsin prepaid approximately $11,182 of debt outstanding under the Aircraft Notes due December 31, 2025. The prepayment of the Aircraft Notes resulted in a gain of approximately Maturities of long-term debt for the years subsequent to December 31, 2021, are as follows: Fiscal Year Amount 2022 $ 5,880 2023 9,170 2024 8,890 2025 43,610 Total $ 67,550 The debt agreements include, among other provisions, certain covenants. At December 31, 2021 and 2020, Air Wisconsin was in compliance with the covenants of all of its debt agreements. 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, 2021
Leases [Abstract]
Lease Obligations	7. Lease Obligations Air Wisconsin has operating leases with terms greater than twelve months for training simulators and facility space including office space and maintenance facilities. The remaining lease terms for training simulators and facility space vary from 4 months to 12 years. For leases with durations longer than 12 months, the Company recorded the related operating lease right-of-use right-of-use guidance. Leasehold improvements are capitalized at cost and amortized over the lesser of their expected useful life or the lease term. Certain leases contain an option to extend or terminate the lease agreement. The Company evaluates each option prior to its expiration and may or may not exercise such option depending on conditions present at the time. At the inception of the lease, if it is reasonably certain that the C As of December 31, 2021, the Company’s right-of-use s and 2020, and $5,398 , , The table below presents operating lease related terms and discount rates as of December 31, 2021: Weighted-average remaining lease term 3.66 years Weighted-average discount rate 5.72 % Components of lease costs were as follows for the years ended December 31, 2021 2020 Operating lease costs $ 4,809 $ 9,326 Short-term lease costs 499 1,662 Variable lease costs 134 (994 ) Lease termination expense — 1,299 Total Lease Costs $ 5,442 $ 11,293 As of December 31, 2021, Air Wisconsin leased or subleased certain training simulators and facilities for terms of greater than 12 months. Rent expense recorded under all operating leases, inclusive of engine leases, was $5,442 and $11,293 in the years ended December 31, 2021 and 2020, respectively. The following table summarizes the future minimum rental payments required under operating leases that had initial or remaining non-cancelable Fiscal Year Amount 2022 $ 6,095 2023 5,832 2024 3,356 2025 2,645 2026 147 Thereafter 511 Total lease payments 18,586 Less imputed interest (2,559 ) Total Lease Liabilities $ 16,027

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	8. Commitments and Contingencies Legal Matters The Company is subject to certain legal proceedings, which it considers routine to its business activities. As of December 31, 2021, the Company believes, after consultation with legal counsel, that the ultimate outcome of such legal proceedings, 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 Payroll Support Program Audit In September 2020, 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 certain provisions of the application for Treasury Payroll Support and the PSP-1 PSP-2 PSP-3 PSP-2 PSP-3 PSP-1 Standby Letters of Credit As of December 31, 2021, Air Wisconsin had six outstanding letters of credit in the aggregate amount of $372 to guarantee the performance of its obligations under certain lease agreements, airport agreements and insurance policies. As of December 31, 2021, Air Wisconsin maintained a credit facility with a borrowing capacity of $820 for the issuance of such letters of credit as needed to support its operations. A significant portion of Air Wisconsin’s restricted cash balance secures the credit facility. Cash Obligations The following table sets forth the Company’s cash obligations for the periods presented: Payment Due for Year Ending December 31, Total 2022 2023 2024 2025 2026 Thereafter Aircraft Notes principal $ 59,500 $ 3,500 $ 7,000 $ 7,000 $ 42,000 $ — $ — Aircraft Notes interest $ 8,050 $ 2,380 $ 2,170 $ 1,890 $ 1,610 $ — $ — Operating lease obligations $ 18,586 $ 6,095 $ 5,832 $ 3,356 $ 2,645 $ 147 $ 511 Total $ 86,136 $ 11,975 $ 15,002 $ 12,246 $ 46,255 $ 147 $ 511 The principal amount of the Aircraft Notes is payable in semi-annual installments of $3,500, and certain additional amounts may be payable based on excess cash flow. The amounts set forth in the table do not reflect any such additional excess cash flow payments. As a result of certain prepayments made under the Aircraft Notes in June 2021, no semi-annual installments are due prior to December 31, 2022. In September 2021 Air Wisconsin paid all outstanding principal and accrued interest on certain loans due in 2022. As of September 30, 2021, all of the Company’s long-term debt was subject to fixed interest rates. For additional information regarding the Aircraft Notes, refer to the section entitled “ Management’s Discussion and Analysis of Financial Condition and Results of Operations – Debt and Credit Facilities Debt

Retirement Plans

Retirement Plans	12 Months Ended
	Dec. 31, 2021
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 2021 and 2020 was $4,358 and $3,764, respectively.

Related-Party Transactions

Related-Party Transactions	12 Months Ended
	Dec. 31, 2021
Related Party Transactions [Abstract]
Related-Party Transactions	10. Related-Party Transactions Southshore leased several CRJ-200 Earnings Per Share and Equity Resource Holdings Associates (Resource Holdings) provides AWAC and Air Wisconsin with financial advisory and management services pursuant to an agreement entered into in January 2012. AWAC paid a total of $240 to Resource Holdings for the years ended December 31, 2021 and December 31, 2020, plus the reimbursement of certain out-of-pocket

Collective Bargaining Agreement

Collective Bargaining Agreements	12 Months Ended
	Dec. 31, 2021
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, 2021, Air Wisconsin was in mediated negotiations with TWU that represents dispatchers. The agreement with the TWU was amendable November 1, 2020, however the negotiation process did not begin until August 17, 2021. 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 September 20, 2023 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, 2021
Earnings Per Share [Abstract]
Earnings Per Share and Equity	12. Earnings Per Share and Equity Calculations of net income per common share for the dates indicated were as follows: 2021 2020 Net income $ 92,626 $ 39,763 Preferred stock dividends 792 759 Net income applicable to common stockholders 91,834 39,004 Weighted average common shares outstanding Shares used in calculating basic earnings per share 54,321 54,863 Stock option 428 559 Series C Preferred 16,500 15,777 Shares used in calculating diluted earnings per share 71,249 71,199 Earnings allocated to common stockholders per common share Basic $ 1.69 0.71 Diluted $ 1.29 0.56 Basic earnings per share of common stock is computed by dividing the net income 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 the conversion of the Series C Preferred into an aggregate of 16,500 shares of common stock under the if-converted years Stock Option Series C Preferred In January 2020, Harbor 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 Harbor filed with the Secretary of State of the State of Delaware. Each share of Series C Preferred was 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). The adjusted Conversion Price as of the date of this filing is $0.15091. 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 into common stock 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 in 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). As of December 31, 2021 , w e In the event of any liquidation, dissolution or winding up of Harbor or a sale of Harbor, the Series C Preferred shall be entitled to receive, prior and in preference to any distribution of any assets of Harbor 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). On March 30, 2021, June 30, 2021, September 28, 2021, and December 31, 2021, the board of directors declared a dividend of $198 on the Series C Preferred, which was paid on March 31, 2021, June 30, 2021, September 30, 2021 and December 30, 2021, respectively. Based on the applicable accounting guidance, Harbor is required to apply the “if-converted” 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 as of December 31, Harbor 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, 2021
Share-based Payment Arrangement [Abstract]
Stock Options	13. Stock Option 2015 Stock Option In 2015, Harbor issued a stock option (the 2015 Stock Option) to purchase 558,835 shares of its common stock at an exercise price of $0.21386 per share. The value of the 2015 Stock Option at the date of grant was deemed to be $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, 2021 and 2020. For additional information, refer to Note 17, Subsequent Events

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	12 Months Ended
	Dec. 31, 2021
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	14. Supplemental Cash Flow Information Cash payments for interest for the years ended December 31, 2021 and 2020 were $3,337 and $7,311, respectively. Cash payments (refunds) for income taxes for the years ended December 31, 2021 and 2020 were $33,956 and $(1,035), respectively. Cash payments included in the measurement of lease liabilities related to operating leases were $4,714 and $5,398 for the years ended December 31, 2021 and 2020 respectively.

Intangible Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	15. Intangible Assets Intangible assets at December 31, 2021 and 2020 consist of the following: December 31, 2021 2020 Gross Carrying Amount Gross Carrying Amount Trade names and air carrier certificate 5,300 5,300 Total $ 5,300 $ 5,300

Stock Repurchase Program

Stock Repurchase Program	12 Months Ended
	Dec. 31, 2021
Stock Repurchase Program [Abstract]
Stock Repurchase Program	16. Stock Repurchase Program On March 30, 2021, the board of directors adopted a stock repurchase program pursuant to which Harbor was authorized to 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 $1,000 per calendar month thereafter. Harbor 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. Harbor acquired 1,547,006 shares of its common stock pursuant to the stock repurchase program during the year ended December 31, 2021. For additional information, refer to Part II, Item 5, “ Purchases of Equity Securities by the Issuer and Affiliated Purchasers

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2021
Subsequent Events [Abstract]
Subsequent Events	17. Subsequent Events The Company evaluated its consolidated financial statements for the year 1 0 • In January 2022, the Company entered into an agreement with one of its stockholders, pursuant to which the Company agreed to repurchase shares of common stock for an aggregate purchase price equal to approxim a pursuant to the settlement of a claim the Company had against the stockholder. • In March 2022, the Company and the holder of the 2015 Stock Option entered into an agreement pursuant to which the 2015 Stock Option was cancelled and terminated in exchange for a cash payment by the Company of approximately $969.2.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
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. (Harbor) and subsidiaries (collectively, the Company). Harbor 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 regional air services 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 (United capacity purchase agreement) with United Airlines, Inc. (United) that was entered into in February 2017 and amended in October 2020 and April 2021. United is currently Air Wisconsin’s sole airline partner. For additional information, refer to Note 3, Capacity Purchase Agreement with United. Air Wisconsin operates as a United Express carrier with a 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 revenues in 2021 and 2020 were derived from operations associated with United.
Contract Revenues	Contract Revenues The Company recognizes revenue under the United capacity purchase agreement over time as services are provided. United pays Air Wisconsin 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 incentive payments available, and penalties payable, primarily based on flight completion, on-time United makes provisional cash payments to Air Wisconsin during each month of service based on projected flight schedules. These provisional cash payments are subsequently reconciled with United based on actual completed flight activity. As of the date of this filing, these payments are reconciled through October 2021. As of December 31, 2021, Air Wisconsin owed United $922, which is recorded in contract liabilities, on the consolidated balance sheets. Under the United capacity purchase agreement, Air Wisconsin is also eligible to receive incentive payments, or may be required to pay penalties, upon the achievement of, or failure to achieve, certain performance criteria. The incentives are defined in the agreement and performance is measured on a monthly basis. At the end of each month during the term of the agreement, Air Wisconsin calculates the incentives achieved, or penalties payable, during that period and recognizes revenue accordingly, subject to the variable constraint guidance under Financial Accounting Standards Board (FASB) Accounting Standards Update (ASU) No. 606, Revenue from Contracts with Customers November and December, 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. Air Wisconsin deferred fixed revenues between April 2020 and June 2021 due to the significant decrease in its completed flights as a result of the COVID-19 Consistent with the analysis above, for the year ended December 31, 2021, as compared to the year ended December 31, 2020, Air Wisconsin also recognized increased non-refundable As part of the CPA Amendment, United issued a note receivable to Air Wisconsin in the amount of $11,048 along with a cash settlement of $670, of which $4,410 was deferred as of December 31, 2020, with the remaining portion to be recognized in proportion to the number of flights expected to be completed in subsequent periods. For the year ended December 31, 2021, Air Wisconsin recorded $1,702 of revenue related to these items, compared to $7,307 of revenue related to these items for the year ended December 31, 2020. In October 2021, in accordance with the CPA Amendment, Air Wisconsin received $294 from United for the opening of a crew base and recognized revenue of $207 using a cumulative catchup adjustment based on prior and future expected departures. In total, Air Wisconsin recognized revenue of $222 and deferred the remaining portion which will be recognized in proportion to the number of flights expected to be completed in subsequent periods. The current portion of the deferred CPA Amendment revenue, in the amount of $2,348, is recorded as part of contract liabilities, and the long-term portion of the deferred CPA Amendment revenue, in the amount of $434, is recorded as long-term contract liabilities on the consolidated balance sheets. The timing of the recognition of deferred fixed revenues, non-refundable The amount of revenues recognized for the year s The CPA Amendment provided, among other things, 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 resulting from the COVID-19
Other Revenues	Other Revenues Other revenues primarily consist of the sales of parts to other airlines and are immaterial in all periods presented. The transaction price for the sale of these parts generally is fair market value.
Cash and Cash Equivalents	Cash and Cash Equivalents Money market funds and investments and deposits with an original maturity of three months or less when acquired are considered cash and cash equivalents.
Restricted Cash	Restricted Cash As of December 31, 2021, the Company had a restricted cash balance of $1,449. A portion of the balance secures a credit facility for the issuance of letters of credit guaranteeing the performance of Air Wisconsin’s obligations under certain lease agreements, airport agreements and insurance policies. The remaining portion is cash held for the repurchase of shares under Harbor’s stock repurchase program. For additional information, refer to Note 8, Commitments and Contingencies Stock Repurchase Program.
Marketable Securities	Marketable Securities The Company’s equity security investments, consisting of exchange-traded funds and mutual funds, are recorded at fair value based on quoted market prices (level 1) in marketable securities on the consolidated balance sheets, in accordance with the guidance in ASC Topic 321, Investments-Equity Securities The calculation of net unrealized gains and losses that relate to marketable securities held as of December 31, 2021 is as follows: Net losses recognized during the period on equity securities $ (1,158 ) Less: Net gains recognized during the period on equity securities sold during the period 2 Unrealized losses recognized during the period on equity securities held as of December 31, 2021 $ (1,160 )
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	Property and Equipment 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 Rotable parts 7 years 10% Spare engines 7 years $ 25 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 visit. Lotus’ engine maintenance costs are expensed. Depreciation expense in 2021 and 2020 was $24,997 and $25,719, 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 required to be performed as of December 31, 2021 and 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, 2021 and 2020.
Maintenance	Maintenance The Company operates its aircraft under a continuous inspection and maintenance program. Generally, the normal cost of recurring maintenance is expensed when incurred. However, we use the deferral method of accounting for Air Wisconsin’s planned major maintenance activities for engines pursuant to which the capitalized engine overhaul costs are amortized over the estimated useful life measured in engine cycles remaining until the next scheduled shop visit.
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 2018. With a few exceptions, the Company is no longer subject to state or local income tax examinations for years prior to 2017. As of December 31, 2021, 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 accrued $57 and $99 for the payment of interest and penalties at December 31, 2021 and 2020, respectively .
Comprehensive Income	Comprehensive Income The Company does not have any components of comprehensive income and, as of December 31, 2021 and 2020, 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 United is currently Air Wisconsin’s sole airline partner. Substantially all the Company’s revenues in the years ended December 31, 2021 and 2020 were derived from the United capacity purchase agreement. For additional information, refer to Note 3, Capacity Purchase Agreement with United
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, particularly in light of the impact of the COVID-19
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company’s financial instruments include cash and cash equivalents, restricted cash, marketable securities, accounts receivable, long-term investments, accounts payable, and long-term debt. The Company believes the carrying amounts of these financial instruments, with the exception of marketable securities, 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. Marketable securities are reported at fair value based on quoted market prices. 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). Fair Value Measurement 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. The table below sets forth the Company’s classification of marketable securities and long-term investments as of: December 31, 2021 Total Level 1 Level 2 Level 3 Marketable securities – exchange-traded funds $ 113,936 $ 113,936 $ — $ — Marketable securities –mutual funds 24,434 24,434 Long-term investments – bonds (see Note 6) 4,275 — 4,275 — Total $ 142,645 $ 138,370 $ 4,275 $ — December 31, 2020 Total Level 1 Level 2 Level 3 Long-term investments – bonds (see Note 6) $ 4,275 $ — $ 4,275 $ — Total $ 4,275 $ — $ 4,275 $ —
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In August 2020, FASB issued ASU No. 2020-06, Debt (Subtopic 470-20); 815-40) 2020-06). 2020-06 2020-06 In August 2018, FASB issued ASU 2018-13, Value Measurements Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement. 2018-13 2018-13 2018-13
Upcoming Accounting Pronouncement	Upcoming Accounting Pronouncement In June 2016, FASB issued ASU 2016-13, Financial Instruments—Credit Losses Measurement of Credit Losses on Financial Instruments 2016-13). 2016-13 2016-13 2016-13

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2021
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 Rotable parts 7 years 10% Spare engines 7 years $ 25 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 net unrealized gains and losses for the period that relate to marketable securities	The calculation of net unrealized gains and losses that relate to marketable securities held as of December 31, 2021 is as follows: Net losses recognized during the period on equity securities $ (1,158 ) Less: Net gains recognized during the period on equity securities sold during the period 2 Unrealized losses recognized during the period on equity securities held as of December 31, 2021 $ (1,160 )
Summary of company's classification of Marketable Securities And Long Term Investments	The table below sets forth the Company’s classification of marketable securities and long-term investments as of: December 31, 2021 Total Level 1 Level 2 Level 3 Marketable securities – exchange-traded funds $ 113,936 $ 113,936 $ — $ — Marketable securities –mutual funds 24,434 24,434 Long-term investments – bonds (see Note 6) 4,275 — 4,275 — Total $ 142,645 $ 138,370 $ 4,275 $ — December 31, 2020 Total Level 1 Level 2 Level 3 Long-term investments – bonds (see Note 6) $ 4,275 $ — $ 4,275 $ — Total $ 4,275 $ — $ 4,275 $ —

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Summary of Income Tax Provision	The income tax provision consists of the following: Year ended December 31, 2021 2020 Current Expense (Benefit) Federal $ 27,084 $ (1,061 ) State 4,382 (80 ) Total Current Expense (Benefit) 31,466 (1,141 ) Deferred (Benefit) Expense Federal (5,405 ) 3,646 State (640 ) (45 ) Total Deferred (Benefit) Expense (6,045 ) 3,601 Income Tax Expense $ 25,421 $ 2,460
Schedule of Effective Income Tax Rate Reconciliation	The following is a reconciliation between a federal income tax rate of 21% and the effective tax rate which is derived by dividing the provision for income taxes by the income before the provision for income taxes: Year ended December 31, 2021 2020 Computed provision for income taxes at the statutory rate $ 24,790 $ 8,867 Increase (decrease) in income taxes resulting from: State income tax provision, net of federal income tax benefit 2,757 875 Non-deductible 52 136 Tax exempt income (2,100 ) — Refundable credits as a result of CARES Act — (936 ) Valuation allowance changes affecting the provision for income taxes — (6,330 ) Return to provision adjustments — (83 ) Other, net (78 ) (69 ) Provision for income taxes $ 25,421 $ 2,460
Components of Deferred Tax Assets and Liabilities	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, 2021 2020 Deferred Tax Assets Accruals and reserves not currently deductible $ 5,647 $ 6,129 Federal NOL and interest expense limitation carryovers — 5,803 State NOL and interest expense limitation carryovers 21 476 Accrued and deferred compensation 2,562 1,966 Prepaid items 891 745 Lease liability 1,033 1,362 December 31, 2021 2020 Contract liability 1,215 1,982 Deferred revenues 11,328 — Unrealized loss on investments 276 — Other 1,266 657 Total Deferred Tax Assets 24,239 19,120 Deferred Tax Liabilities Property and equipment (22,607 ) (23,268 ) Right-of-use (1,663 ) (2,046 ) Other (124 ) (6 ) Total Deferred Tax Liabilities (24,394 ) (25,320 ) Net Deferred Income Tax Liabilities $ (155 ) $ (6,200 )
Schedule of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of unrecognized tax benefits for the years ended December 31, 2021 and 2020 is as follows: December 31, 2021 2020 Unrecognized tax benefits at the beginning of the year $ 177 $ 248 Gross decreases – lapse of statute (59 ) (71 ) Unrecognized tax benefits at the end of the year $ 118 $ 177 Interest and penalties in year-end $ 57 $ 99

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Schedule of Long-term Debt	Long-term debt consists of the following (with interest rates, as of December 31, 2021 and December 31, 2020): December 31, 2021 2020 Notes, due December 31, 2025, 4.0% (a) $ 67,550 $ 80,850 Credit Agreements, due through 2022, 5.0% (b) — 26,988 SBA Loan, due 2025, 1.0% (c) — 10,000 Total debt 67,550 117,838 Less: current maturities 5,880 23,652 Long-Term Debt $ 61,670 $ 94,186
Schedule of Maturities of Long-Term Debt	Maturities of long-term debt for the years subsequent to December 31, 2021, are as follows: Fiscal Year Amount 2022 $ 5,880 2023 9,170 2024 8,890 2025 43,610 Total $ 67,550

Lease Obligations (Tables)

Lease Obligations (Tables)	12 Months Ended
	Dec. 31, 2021
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, 2021: Weighted-average remaining lease term 3.66 years Weighted-average discount rate 5.72 %
Schedule of Component of Lease Cost	Components of lease costs were as follows for the years ended December 31, 2021 2020 Operating lease costs $ 4,809 $ 9,326 Short-term lease costs 499 1,662 Variable lease costs 134 (994 ) Lease termination expense — 1,299 Total Lease Costs $ 5,442 $ 11,293
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 2022 $ 6,095 2023 5,832 2024 3,356 2025 2,645 2026 147 Thereafter 511 Total lease payments 18,586 Less imputed interest (2,559 ) Total Lease Liabilities $ 16,027

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Schedule of Cash Obligations	The following table sets forth the Company’s cash obligations for the periods presented: Payment Due for Year Ending December 31, Total 2022 2023 2024 2025 2026 Thereafter Aircraft Notes principal $ 59,500 $ 3,500 $ 7,000 $ 7,000 $ 42,000 $ — $ — Aircraft Notes interest $ 8,050 $ 2,380 $ 2,170 $ 1,890 $ 1,610 $ — $ — Operating lease obligations $ 18,586 $ 6,095 $ 5,832 $ 3,356 $ 2,645 $ 147 $ 511 Total $ 86,136 $ 11,975 $ 15,002 $ 12,246 $ 46,255 $ 147 $ 511

Earnings Per Share and Equity (

Earnings Per Share and Equity (Tables)	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Schedule of Calculations of Net Income Per Common Share	Calculations of net income per common share for the dates indicated were as follows: 2021 2020 Net income $ 92,626 $ 39,763 Preferred stock dividends 792 759 Net income applicable to common stockholders 91,834 39,004 Weighted average common shares outstanding Shares used in calculating basic earnings per share 54,321 54,863 Stock option 428 559 Series C Preferred 16,500 15,777 Shares used in calculating diluted earnings per share 71,249 71,199 Earnings allocated to common stockholders per common share Basic $ 1.69 0.71 Diluted $ 1.29 0.56

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets	Intangible assets at December 31, 2021 and 2020 consist of the following: December 31, 2021 2020 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	1 Months Ended	6 Months Ended		12 Months Ended
	Oct. 31, 2021	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2021	Dec. 31, 2020
Summary of Significant Accounting Policies [Line Items]
Depreciation expense				$ 24,997	$ 25,719
Accrued payment of interest and penalties		$ 57		57	99
Long-term note receivable		$ 47,568		$ 47,568	32,440
Notes Receivable Instrument, Interest Rate		4.50%		4.50%
Notes Receivable Instrument, Maturity Date				Feb. 28, 2023
Interest Receivable		$ 2,166		$ 2,166
Impairment of Intangible Assets, Indefinite-lived				0	0
Deferred revenue recognized				18,650	7,116
Revenue, Performance Obligation				15,128	21,392
Cash Settlement					670
Note Receivable					11,048
Contract with Customer, Liability, Current		43,890		43,890	18,443
Payments for proceeds from incentives and penalties				3,028	3,809
Cash Received From United For The Opening Of A Crew Base	$ 294
Restricted Cash		1,449		1,449
Marketable securities		138,370		138,370	0
Deferred Revenue Recognition	207			378
Current Liabilities [Member]
Summary of Significant Accounting Policies [Line Items]
Contract with Customer, Liability, Current		922		922
October 2020 Amendment [Member]
Summary of Significant Accounting Policies [Line Items]
Deferred revenue current		2,348		2,348	4,828
Deferred Revenue, Noncurrent		434		434	892
Deferred Cash Settlement due from United					4,410
Deferred Revenue Recognition				1,702	7,307
Air Wisconsin [Member]
Summary of Significant Accounting Policies [Line Items]
Deferred revenue current		35,792		35,792
Deferred Revenue, Noncurrent		9,046		9,046
Upfront fee				3,593	2,504
Fulfillment costs				385	269
Cumulative Catchup Adjustment		462		462
Deferred Revenue		495		$ 495
Deferred Revenue Recognition	$ 222	$ 13,355	$ 15,351		$ 43,220

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, 2021USD ($)
Property, Plant and Equipment [Line Items]
Property Plant And Equipment Useful Life	7 years
Aircraft [Member]
Property, Plant and Equipment [Line Items]
Current Residual Value	$ 50
Rotable Parts [Member]
Property, Plant and Equipment [Line Items]
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
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 company's classification of Marketable Securities And Long Term Investments (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instruments, Owned, at Fair Value	$ 142,645	$ 4,275
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instruments, Owned, at Fair Value	138,370
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instruments, Owned, at Fair Value	4,275	4,275
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instruments, Owned, at Fair Value	0
Marketable securities – exchange-traded funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instruments, Owned, at Fair Value	113,936
Marketable securities – exchange-traded funds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instruments, Owned, at Fair Value	113,936
Marketable securities – exchange-traded funds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instruments, Owned, at Fair Value	0
Marketable securities – exchange-traded funds | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instruments, Owned, at Fair Value	0
Marketable securities –mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instruments, Owned, at Fair Value	24,434
Marketable securities –mutual funds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instruments, Owned, at Fair Value	24,434
Long-term investments – bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instruments, Owned, at Fair Value	4,275	4,275
Long-term investments – bonds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instruments, Owned, at Fair Value	0
Long-term investments – bonds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instruments, Owned, at Fair Value	4,275	$ 4,275
Long-term investments – bonds | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instruments, Owned, at Fair Value	$ 0

Summary of Significant Accoun_7

Summary of Significant Accounting Policies- Summary of net unrealized gains and losses for the period that relate to marketable securities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Marketable Securities, Gain (Loss) [Abstract]
Net losses recognized during the period on equity securities	$ (1,158)	$ 0
Less: Net gains recognized during the period on equity securities sold during the period	2
Unrealized losses recognized during the period on equity securities held as of December 31, 2021	$ (1,160)

Liquidity - Additional Informat

Liquidity - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Liquidity Uncertainty And Going Concern [Line Items]
Interest rate	4.50%
Gain (Loss) on Extinguishment of Debt	$ 10,363	$ 0
Small Business Administration Payroll Protection Program [Member] | Paycheck Protection Program Notes [Member]
Liquidity Uncertainty And Going Concern [Line Items]
Gain (Loss) on Extinguishment of Debt	$ 10,135
Small Business Administration Payroll Protection Program [Member] | Air Wisconsin [Member]
Liquidity Uncertainty And Going Concern [Line Items]
Interest rate	1.00%
Amount received from Small Business Administration under PPP		10,000
Treasury Department Payroll Support Program [Member]
Liquidity Uncertainty And Going Concern [Line Items]
Payroll Support Agreement Awardable Amount		42,185
PSP2 Agreement [member] | Air Wisconsin [Member] | Maximum [member]
Liquidity Uncertainty And Going Concern [Line Items]
Proceeds from cares act payroll support program grant	$ 32,987
CARES Act Payroll Support Program [member] | Air Wisconsin [Member]
Liquidity Uncertainty And Going Concern [Line Items]
Proceeds from cares act payroll support program grant	66,316
Payroll Support Program Contra Expense	66,316	$ 42,185
PSP3 Agreement [member] | Air Wisconsin [Member]
Liquidity Uncertainty And Going Concern [Line Items]
Cares act payroll support program grant receivable	$ 33,329

Capacity Purchase Agreement w_2

Capacity Purchase Agreement with United - Additional Information (Detail) - United Airlines [Member] - CRJ-200 [Member] - Aircraft	1 Months Ended	12 Months Ended
	Feb. 28, 2017	Dec. 31, 2021
Date of expiration of the agreement	Feb. 1, 2023
Maximum [member]
Number of aircraft operated	65	63

Property and Equipment - Additi

Property and Equipment - Additional Information (Detail) $ in Thousands	May 20, 2020USD ($)	Sep. 30, 2020USD ($)	Dec. 31, 2021Aircraft
Property, Plant and Equipment [Line Items]
Aggregate purchase price for aircraft acquired | $	$ 3,000	$ 818
CRJ-200 [Member]
Property, Plant and Equipment [Line Items]
Number of aircraft acquired | Aircraft			64

Income Taxes - Summary of incom

Income Taxes - Summary of income tax provision (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Current Expense (Benefit)
Federal	$ 27,084	$ (1,061)
State	4,382	(80)
Total Current Expense (Benefit)	31,466	(1,141)
Deferred (Benefit) Expense
Federal	(5,405)	3,646
State	(640)	(45)
Total Deferred (Benefit) Expense	(6,045)	3,601
Income Tax Expense	$ 25,421	$ 2,460

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Line Items]
Effective Income Tax Rate, Federal statutory rate	21.00%
Valuation allowance release against certain deferred tax assets		$ 6,330
Estimated effective tax rate applicable to federal net operating losses	21.00%
Estimated effective tax rate applicable to state net operating losses	0.05%
Federal [Member]
Income Tax Disclosure [Line Items]
Net operating losses	$ 0	27,583
State [Member]
Income Tax Disclosure [Line Items]
Net operating losses	$ 731	$ 9,147

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Effective income tax rate reconciliation
Computed provision for income taxes at the statutory rate	$ 24,790	$ 8,867
State income tax provision, net of federal income tax benefit	2,757	875
Non-deductible expenses	52	136
Tax exempt income	(2,100)	0
Refundable credits as a result of CARES Act	0	(936)
Valuation allowance changes affecting the provision for income taxes	0	(6,330)
Return to provision adjustments	0	(83)
Other, net	(78)	(69)
Income Tax Expense	$ 25,421	$ 2,460

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred Tax Assets
Accruals and reserves not currently deductible	$ 5,647	$ 6,129
Federal NOL and interest expense limitation carryovers	0	5,803
State NOL and interest expense limitation carryovers	21	476
Accrued and deferred compensation	2,562	1,966
Prepaid items	891	745
Lease liability	1,033	1,362
Contract liability	1,215	1,982
Deferred revenues	11,328	0
Unrealized loss on investments	276	0
Other	1,266	657
Total Deferred Tax Assets	24,239	19,120
Deferred Tax Liabilities
Property and equipment	(22,607)	(23,268)
Right-of-use asset	(1,663)	(2,046)
Other	(124)	(6)
Total Deferred Tax Liabilities	(24,394)	(25,320)
Net Deferred Income Tax Liabilities	$ (155)	$ (6,200)

Income Taxes - Schedule of unre

Income Taxes - Schedule of unrecognized tax benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Unrecognized tax benefits
Unrecognized tax benefits at the beginning of the year	$ 177	$ 248
Gross decreases - lapse of statute	(59)	(71)
Unrecognized tax benefits at the end of the year	118	177
Interest and penalties in year-end balance	$ 57	$ 99

Debt - Schedule Of Long Term De

Debt - Schedule Of Long Term Debt (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Total debt	$ 67,550	$ 117,838
Less: current maturities	5,880	23,652
Long-Term Debt	61,670	94,186
Notes Due December 31, 2025 [Member]
Total debt	67,550	80,850
Credit Agreements Due Through 2022 [Member]
Total debt	0	26,988
SBA Loan Due 2025 [Member]
Total debt	$ 0	$ 10,000

Debt - Schedule Of Long Term _2

Debt - Schedule Of Long Term Debt (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2025	Dec. 31, 2020	Apr. 30, 2020	Dec. 31, 2019	Feb. 24, 2018
Aggregate principal amount		$ 70,000
Future undiscounted interest payments	$ 8,050
Aircraft Notes [Member]
Aggregate principal amount					$ 70,000	$ 70,000
Future undiscounted interest payments			$ 10,850
Debt Instrument, Periodic Payment	$ 3,500
Paycheck Protection Program Due 2025 [Member]
Aggregate principal amount				$ 10,000
Credit Agreement [Member] | Credit Agreements Due Through 2022 [Member]
Line of credit, maturity date	Dec. 31, 2020
Second Credit Agreement [Member] | Credit Agreements Due Through 2022 [Member]
Line of credit, maturity date	Jun. 30, 2022

Debt - Additional information (

Debt - Additional information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended
	Aug. 31, 2021	Sep. 30, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2025	Jun. 30, 2021	Dec. 31, 2019	Feb. 24, 2018	Jul. 31, 2003
Aggregate principal amount					$ 70,000
Operating lease right of use asset			$ 18,679	$ 8,582
Gain (Loss) on Extinguishment of Debt			10,363	0
Hangar [Member]
Operating lease right of use asset			$ 2,778	$ 3,010
Aircraft Notes [Member]
Aggregate principal amount							$ 70,000	$ 70,000
Gain (Loss) on Extinguishment of Debt		$ 228
City of Milwaukee, Wisconsin variable rate Industrial Development Bonds [Member]
Aggregate principal amount									$ 4,275
Paycheck Protection Program Notes [Member] | Hrbrsba Loan Member [Member]
Gain (Loss) on Extinguishment of Debt	$ 10,135
Notes Due December Thirty One Two Thousand And Twenty Five Prepaid [Member]
Aggregate principal amount						$ 11,182

Debt - Schedule of Maturities o

Debt - Schedule of Maturities of Long-term Debt (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Maturities of Long-term Debt [Abstract]
2022	$ 5,880
2023	9,170
2024	8,890
2025	43,610
Total	$ 67,550	$ 117,838

Lease Obligations - Additional

Lease Obligations - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Operating lease right of use asset	$ 18,679	$ 8,582
Current portion of operating lease liability	5,150	1,361
Long-term operating lease liability	10,877	4,351
Cash payments included in the measurement of lease liabilities related to operating leases	4,714	5,398
Operating lease rent expense	$ 5,442	$ 11,293
Minimum [Member]
Lessee, Lease, Description [Line Items]
Lease term of training simulators	12 months
Operating Lease Remaining Lease	4 months
Maximum [Member]
Lessee, Lease, Description [Line Items]
Operating Lease Remaining Lease	12 years

Lease Obligations - Summary Of

Lease Obligations - Summary Of Weighted average Terms and Discount Rate For Operating Leases (Detail)	Dec. 31, 2021
Leases [Abstract]
Weighted-average remaining lease term	3 years 7 months 28 days
Weighted-average discount rate	5.72%

Lease Obligations - Schedule of

Lease Obligations - Schedule of Component Of Lease Cost (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Lease, Cost [Abstract]
Operating lease costs	$ 4,809	$ 9,326
Short-term lease costs	499	1,662
Variable lease costs	134	(994)
Lease termination expense	0	1,299
Total Lease Costs	$ 5,442	$ 11,293

Lease Obligations - Schedule _2

Lease Obligations - Schedule of Future Minimum Lease Payments Under Non-Cancelable Operating Leases (Detail) $ in Thousands	Dec. 31, 2021USD ($)
Leases [Abstract]
2022	$ 6,095
2023	5,832
2024	3,356
2025	2,645
2026	147
Thereafter	511
Total lease payments	18,586
Less imputed interest	(2,559)
Total Lease Liabilities	$ 16,027

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Thousands	Dec. 31, 2021USD ($)Letter_Of_Credit
Other Commitments [Line Items]
Number of outstanding letters of credit | Letter_Of_Credit	6
Air Wisconsin [Member]
Other Commitments [Line Items]
Outstanding credit facility	$ 820
Aircraft Notes principal [Member]
Other Commitments [Line Items]
Semi-Annual Principal amount of notes payable	3,500
Letter of Credit [Member]
Other Commitments [Line Items]
Outstanding credit facility	$ 372

Commitments and Contingencies_2

Commitments and Contingencies - Cash Obligations (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Contractual Obligation Fiscal Year Maturity [Line Items]
Long-term debt, Total	$ 67,550	$ 117,838
Long-term debt, due in 2022	5,880
Long-term debt, due in 2023	9,170
Long-term debt, due in 2024	8,890
Long-term debt, due in 2025	43,610
Total lease payments	18,586
Operating lease obligations, due in 2022	6,095
Operating lease obligations, due in 2023	5,832
Operating lease obligations, due in 2024	3,356
Operating lease obligations, due in 2025	2,645
Operating lease obligations, due in 2026	147
Operating lease obligations, due Thereafter	511
Total cash obligations	86,136
Total cash obligations, due in 2022	11,975
Total cash obligations, due in 2023	15,002
Total cash obligations, due in 2024	12,246
Total cash obligations, due in 2025	46,255
Total cash obligations, due in 2026	147
Total cash obligations, due Thereafter	511
Aircraft Notes Principal [Member]
Contractual Obligation Fiscal Year Maturity [Line Items]
Long-term debt, Total	59,500
Long-term debt, due in 2022	3,500
Long-term debt, due in 2023	7,000
Long-term debt, due in 2024	7,000
Long-term debt, due in 2025	42,000
Long-term debt, due in 2026	0
Aircraft Notes Interest [Member]
Contractual Obligation Fiscal Year Maturity [Line Items]
Long-term debt, Total	8,050
Long-term debt, due in 2022	2,380
Long-term debt, due in 2023	2,170
Long-term debt, due in 2024	1,890
Long-term debt, due in 2025	1,610
Long-term debt, due in 2026	$ 0

Retirement Plans - Additional I

Retirement Plans - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Retirement Benefits [Abstract]
Total expense under defined contribution retirement plans	$ 4,358	$ 3,764

Related-Party Transactions - Ad

Related-Party Transactions - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	Jan. 17, 2020	Jan. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Related Party Transaction [Line Items]
Operating lease agreements term			April 2010 through January 2020
Annual recurring fee payable monthly pursuant to service agreement			$ 150
Payment For Management services fee			113
Series C Redeemable Convertible Preferred Stock [Member]
Related Party Transaction [Line Items]
Common stock issuable upon conversion of temporary equity		16,500
Southshore [Member] | CRJ-200 [Member]
Related Party Transaction [Line Items]
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		4,000
Business acquisition shares issued or issuable value		$ 13,200
Business acquisiton shares		$ 3.30
Air Wisconsin [Member] | Southshore [Member]
Related Party Transaction [Line Items]
Payments to related parties pursuant to certain aircraft and engines leases and for other professional services	$ 150
AWAC Aviation Inc [Member] | Financial Advisory And Management Services [Member]
Related Party Transaction [Line Items]
Payment For Management services fee			$ 240	$ 240

Earnings Per Share and Equity -

Earnings Per Share and Equity - Calculations of Net Income Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Earnings Per Share Reconciliation [Abstract]
Net income	$ 92,626	$ 39,763
Preferred stock dividends	792	759
Net income applicable to common stockholders	$ 91,834	$ 39,004
Weighted average common shares outstanding
Shares used in calculating basic earnings per share	54,321	54,863
Stock option	428	559
Series C Preferred	16,500	15,777
Shares used in calculating diluted earnings per share	71,249	71,199
Earnings allocated to common stockholders per common share
Basic	$ 1.69	$ 0.71
Diluted	$ 1.29	$ 0.56

Earnings Per Share and Equity_2

Earnings Per Share and Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Sep. 28, 2021	Jun. 30, 2021	Mar. 30, 2021	Jan. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Class of Stock [Line Items]
Preferred stock, liquidation preference	$ 0.80
Common stock, convertible, conversion price							$ 0.15091
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements							428	559
Percentage of the diluted capital stock							23.60%
Common Stock [Member]
Class of Stock [Line Items]
Convertible preferred stock, shares issued upon conversion		16,500,000					16,500,000
Series C Redeemable Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Temporary Equity:Conversion Cap Excess Shares						4,000,000
Dividend declared		$ 198	$ 198	$ 198	$ 198
Date of dividend declaration		Dec. 31, 2021	Sep. 28, 2021	Jun. 30, 2021	Mar. 30, 2021
Date of dividend payment		Dec. 30, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021
Temporary Equity, Shares Outstanding		4,000,000					4,000,000	4,000,000
Common stock converted							16,500
Series C Preferred Stock [Member]
Class of Stock [Line Items]
Temporary Equity:Conversion Cap Excess Shares							3,245
Percentage of diluted shares of capital stock		23.60%					23.60%
Temporary Equity, Shares Outstanding		755					755
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements							428	559
Series C Preferred Stock [Member] | Forecast [Member]
Class of Stock [Line Items]
Conversion of preferred stock, maximum amount converted	$ 16,500
Cumulative quarterly preferred stock dividend rate increase after Dec.31, 2022	0.50%

Stock Options - Additional Info

Stock Options - Additional Information (Detail) - 2015 Stock Option [Member] - $ / shares	12 Months Ended
	Dec. 31, 2021	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, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Cash payments for interest	$ 3,337	$ 7,311
Cash payments for income taxes	33,956	(1,035)
Cash payments included in the measurement of lease liabilities related to operating leases	$ 4,714	$ 5,398

Intangible Assets - Components

Intangible Assets - Components of Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Trade names and air carrier certificate	$ 5,300	$ 5,300
Total	$ 5,300	$ 5,300

Stock Repurchase Program- Addit

Stock Repurchase Program- Additional Information (Detail) - Common Stock [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Mar. 30, 2021
Equity, Class of Treasury Stock [Line Items]
Stock Repurchased During Period, Shares	(1,547,000)
Stock Repurchase Program [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount in First Calendar Month		$ 1,000
Stock Repurchase Program, Authorized Amount to be Repurchased Each Month		1,000
Stock Repurchased During Period, Shares	1,547,006

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($) shares in Thousands	Mar. 31, 2022	Jan. 31, 2022	Dec. 31, 2021
Common Stock [Member]
Subsequent Event [Line Items]
Stock Repurchased During Period, Shares			(1,547)
Subsequent Event [Member]
Subsequent Event [Line Items]
Share Based Arrangement Cash Payment For Stock Options Cancellation and Termination	$ 969,200
Subsequent Event [Member] | Common Stock [Member]
Subsequent Event [Line Items]
Future stock repurchase program adopted, value		$ 5,655,000
Stock Repurchased During Period, Shares		5,437,500