Allegiant Travel (ALGT) 10-Q 5 May 21 2021 Q1 Quarterly report Financial data

Cover Page

Cover Page - $ / shares	3 Months Ended
	Mar. 31, 2021	Apr. 26, 2021	Dec. 31, 2020
Document and Entity Information [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	001-33166
Entity Registrant Name	Allegiant Travel Co
Entity Incorporation, State or Country Code	NV
Entity Tax Identification Number	20-4745737
Entity Address, Address Line One	1201 North Town Center Drive
Entity Address, City or Town	Las Vegas,
Entity Address, State or Province	NV
Entity Address, Postal Zip Code	89144
City Area Code	702
Local Phone Number	851-7300
Title of 12(b) Security	Common stock, par value $.001
Trading Symbol	ALGT
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	true
Entity Common Stock, Shares Outstanding		16,416,019
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Entity Central Index Key	0001362468
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Common Stock, Par or Stated Value Per Share	$ 0.001	$ 0.001	$ 0.001

Consolidated Balance Sheets (Cu

Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Common Stock, Par or Stated Value Per Share	$ 0.001	$ 0.001
CURRENT ASSETS
Cash and cash equivalents	$ 301,615	$ 152,764
Restricted cash	25,212	17,555
Short-term investments	426,381	532,477
Accounts receivable	188,116	192,215
Expendable parts, supplies and fuel, net	26,276	24,006
Prepaid expenses and other current assets	32,088	24,616
TOTAL CURRENT ASSETS	999,688	943,633
Property and equipment, net	2,072,211	2,050,311
Deferred major maintenance, net	131,910	127,463
Operating lease right-of-use assets, net	116,998	115,911
Deposits and other assets	24,393	21,607
TOTAL ASSETS:	3,345,200	3,258,925
CURRENT LIABILITIES
Accounts payable	37,767	34,197
Accrued liabilities	129,795	116,093
Current operating lease liabilities	15,247	14,313
Air traffic liability	403,049	307,508
Current maturities of long-term debt and finance lease obligations, net of related costs	156,482	217,234
TOTAL CURRENT LIABILITIES	742,340	689,345
Long-term debt and finance lease obligations, net of current maturities and related costs	1,459,570	1,441,777
Deferred income taxes	303,390	301,763
Noncurrent operating lease liabilities	103,103	102,289
Other noncurrent liabilities	27,143	24,388
TOTAL LIABILITIES:	2,635,546	2,559,562
SHAREHOLDERS' EQUITY
Common stock, par value $.001	23	23
Treasury shares	(646,008)	(646,008)
Additional paid in capital	333,147	329,753
Accumulated other comprehensive income (loss), net	1	(27)
Retained earnings	1,022,491	1,015,622
TOTAL EQUITY:	709,654	699,363
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY:	$ 3,345,200	$ 3,258,925

Consolidated Statements of Inco

Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
OPERATING REVENUES:
Passenger	$ 256,695	$ 378,911
Third party products	13,622	15,976
Fixed fee contracts	7,692	8,919
Other	1,115	5,375
Total operating revenues	279,124	409,181
OPERATING EXPENSES:
Salary and benefits	117,950	112,646
Aircraft fuel	82,848	88,813
Station operations	43,094	40,999
Depreciation and amortization	43,174	43,699
Maintenance and repairs	23,371	21,795
Sales and marketing	11,609	18,455
Aircraft lease rental	4,720	962
Other	17,776	26,717
Payroll Support Programs grant recognition	91,758	0
Special charges	1,738	172,900
Total operating expenses	254,522	526,986
OPERATING INCOME (LOSS)	24,602	(117,805)
OTHER (INCOME) EXPENSES:
Interest expense	16,788	18,153
Capitalized interest	0	(4,067)
Interest income	(463)	(2,311)
Loss on debt extinguishment	0	1,222
Other, net	(393)	(76)
Total other expenses	15,932	12,921
INCOME (LOSS) BEFORE INCOME TAXES	8,670	(130,726)
INCOME TAX PROVISION (BENEFIT)	1,801	(97,717)
NET INCOME (LOSS)	$ 6,869	$ (33,009)
Earnings (loss) per share to common shareholders:
Basic	$ 0.42	$ (2.08)
Earnings Per Share, Diluted	$ 0.42	$ (2.08)
Shares used for computation:
Basic	16,167	15,952
Diluted	16,167	15,952
Cash dividends declared per share:	$ 0	$ 0.70

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest, Total	$ 6,869	$ (33,009)
Other comprehensive income (loss):
Change in available for sale securities, net of tax	28	(733)
Foreign currency translation adjustments	0	11
Total other comprehensive income (loss)	28	(722)
TOTAL COMPREHENSIVE INCOME (LOSS)	$ 6,897	$ (33,731)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity Statement - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	AOCI Attributable to Parent	Retained Earnings	Treasury Stock
Common Stock, Shares, Outstanding		16,303
Stockholders' Equity Attributable to Parent	$ 883,551		$ 289,933	$ 98	$ 1,211,076	$ (617,579)
Common stock, par value $.001		$ 23
StockIssuedDuringPeriodSharesStockOptionsSARsExercised		113
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	5,334		5,334
Treasury Stock, Shares, Acquired		217
Treasury Stock, Value, Acquired, Cost Method	(33,773)					(33,773)
Dividends	(11,478)				(11,478)
Payments of Dividends	11,478
Other Comprehensive Income (Loss), Net of Tax	(722)			(722)
NET INCOME (LOSS)	(33,009)				(33,009)
Common Stock, Shares, Outstanding		16,199
Stockholders' Equity Attributable to Parent	809,903		295,267	(624)	1,166,589	(651,352)
Common stock, par value $.001		$ 23
Common Stock, Shares, Outstanding		16,405
Stockholders' Equity Attributable to Parent	699,363		329,753	(27)	1,015,622	(646,008)
Common stock, par value $.001	23	$ 23
StockIssuedDuringPeriodSharesStockOptionsSARsExercised		11
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	3,394		3,394
Payments of Dividends	0
Other Comprehensive Income (Loss), Net of Tax	28			28
NET INCOME (LOSS)	6,869				6,869
Common Stock, Shares, Outstanding		16,416
Stockholders' Equity Attributable to Parent	709,654		$ 333,147	$ 1	$ 1,022,491	$ (646,008)
Common stock, par value $.001	$ 23	$ 23

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity Parentheticals - $ / shares	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Stockholders' Equity [Abstract]
Common Stock, Dividends, Per Share, Declared	$ 0	$ 0.70

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Statement of Cash Flows [Abstract]
Net income (loss)	$ 6,869	$ (33,009)
Depreciation and amortization	43,174	43,699
Special charges	1,738	163,360
Other adjustments	8,318	67,890
Air traffic liability	95,541	53,885
Other - net	12,353	(189,508)
Net cash provided by operating activities	167,993	106,317
Cash flows from investing activities:
Purchase of investment securities	(89,338)	(105,382)
Proceeds from maturities of investment securities	194,534	130,720
Purchase of property and equipment	(69,499)	(134,483)
Other investing activities	(16)	2,283
Net cash provided by (used in) investing activities	35,681	(106,862)
Cash flows from financing activities:
Cash dividends paid to shareholders	0	(11,478)
Proceeds from the issuance of debt and finance lease obligations	105,000	128,296
Repurchase of common stock	0	(33,773)
Principal payments on debt and finance lease obligations	(151,517)	(62,723)
Debt issuance costs	(649)	(2,530)
Net cash provided by (used in) financing activities	(47,166)	17,792
NET CHANGE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	156,508	17,247
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH AT BEGINNING OF PERIOD	170,319	136,785	$ 136,785
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH AT END OF PERIOD	326,827	154,032	170,319
CASH PAYMENTS (RECEIPTS) FOR:
Interest paid, net of amount capitalized	15,059	12,031
Income tax payments (refunds)	(138)	22
Right-of-use (ROU) assets acquired	4,733	50,218
Purchases of property and equipment in accrued liabilities	$ 4,064	$ 46,452	$ 16,900

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited consolidated financial statements include the accounts of Allegiant Travel Company (the “Company”) and its majority-owned operating subsidiaries. The Company's investments in unconsolidated affiliates, which are 50 percent or less owned, are accounted for under the equity or cost method, and are insignificant to the consolidated financial statements. All intercompany balances and transactions have been eliminated. These unaudited consolidated financial statements reflect all normal recurring adjustments which management believes are necessary to present fairly the financial position, results of operations, and cash flows of the Company for the respective periods presented. Certain information and footnote disclosures normally included in the annual consolidated financial statements prepared in accordance with U.S. generally accepted accounting principles ("U.S. GAAP") have been omitted pursuant to the rules and regulations of the Securities and Exchange Commission for Form 10-Q. These unaudited interim consolidated financial statements should be read in conjunction with the audited consolidated financial statements of the Company and notes thereto included in the annual report of the Company on Form 10-K for the year ended December 31, 2020 and filed with the Securities and Exchange Commission. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and 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 may differ from these estimates. Recent Accounting Pronouncements

COVID-19 (Notes)

COVID-19 (Notes)	3 Months Ended
	Mar. 31, 2021
Unusual or Infrequent Items, or Both [Abstract]
Unusual or Infrequent Items, or Both, Disclosure [Text Block]	Impact of the COVID-19 Pandemic The rapid spread of COVID-19 and the related government restrictions, social distancing measures, and consumer fears have impacted flight loads, resulted in unprecedented cancellations of bookings and substantially reduced demand for new bookings throughout the airline industry. Starting in March 2020, the Company experienced a severe reduction in air travel, which continued through the first quarter of 2021. Demand in the foreseeable future will continue to be affected by fluctuations in COVID-19 cases, hospitalizations, deaths, treatment efficacy and the availability of vaccines. The Company is continuously reevaluating flight schedules and adjusting capacity based on demand trends. On December 27, 2020, the Consolidated Appropriations Act, 2021 (the "Payroll Support Program Extension") was signed into law. This Payroll Support Program Extension provides an additional $15.0 billion in support to the airline industry. On January 15, 2021, the Company through its airline operating subsidiary Allegiant Air, LLC entered into a Payroll Support Program Extension Agreement (the “PSP2”) with the Treasury under the Payroll Support Program Extension. The Company received two installments of $45.9 million each in January and March 2021 for a total of $91.8 million under the Payroll Support Program Extension. The funds were used exclusively for wages, salaries and benefits. During 2020, the Company made significant progress on strengthening its liquidity by suspending all stock buybacks and dividends; executives temporarily reducing their salaries by 50 percent and temporarily foregoing cash compensation of Board members; enacting a hiring freeze and offering voluntary leave; eliminating cash bonuses; suspending all non-essential capital expenditures including, but not limited to, Sunseeker Resorts, Teesnap and Allegiant Nonstop family entertainment centers; and extending payment terms and renegotiating contracts with vendors. Given the Company's efforts to conserve and raise liquidity and the Company's assumptions about the future impact of COVID-19 on travel demand, which could be materially different due to the inherent uncertainties of the current operating environment, the Company expects to meet its cash obligations as well as remain in compliance with the debt covenants in its existing financing agreements for the next 12 months based on its current level of unrestricted cash and short-term investments, its anticipated access to liquidity and tax refunds, and projected cash flows from operations. Special Charges The table below summarizes special charges recorded during the three months ended March 31, 2021. Three Months Ended March 31, (in thousands) 2021 2020 Operating $ 1,738 $ 166,098 Non-operating — 6,802 Total special charges $ 1,738 $ 172,900 Additional detail for the $1.7 million of total special charges for the three months ended March 31, 2021 appears below: • $1.2 million resulting from the accelerated retirements of two airframes and three engines • $0.5 million related to an impairment loss on a building in Chesterfield, Missouri associated with the Allegiant Nonstop family entertainment line of business. In the first quarter 2020, the onset of COVID-19 triggered an impairment review of long lived assets and a non-cash impairment charge of $163.4 million was recognized. The Company also identified $9.5 million of expenses, primarily comprised of salary and benefits, that were unique and specific to COVID-19.
Restructuring and Related Activities Disclosure [Text Block]	Special Charges The table below summarizes special charges recorded during the three months ended March 31, 2021. Three Months Ended March 31, (in thousands) 2021 2020 Operating $ 1,738 $ 166,098 Non-operating — 6,802 Total special charges $ 1,738 $ 172,900 Additional detail for the $1.7 million of total special charges for the three months ended March 31, 2021 appears below: • $1.2 million resulting from the accelerated retirements of two airframes and three engines • $0.5 million related to an impairment loss on a building in Chesterfield, Missouri associated with the Allegiant Nonstop family entertainment line of business. In the first quarter 2020, the onset of COVID-19 triggered an impairment review of long lived assets and a non-cash impairment charge of $163.4 million was recognized. The Company also identified $9.5 million of expenses, primarily comprised of salary and benefits, that were unique and specific to COVID-19.

Revenue Recognition

Revenue Recognition	3 Months Ended
	Mar. 31, 2021
Revenue Recognition [Abstract]
Revenue from Contract with Customer [Text Block]	Revenue Recognition Passenger Revenue Passenger revenue is the most significant category in our reported operating revenues, as outlined below: Three Months Ended March 31, (in thousands) 2021 2020 Scheduled service $ 131,929 $ 197,261 Ancillary air-related charges 121,072 176,964 Co-brand redemptions 3,694 4,686 Total passenger revenue $ 256,695 $ 378,911 Sales of passenger tickets not yet flown are recorded in air traffic liability. Passenger revenue is recognized when transportation is provided or when ticket voucher breakage occurs, to the extent different from estimated breakage. As of March 31, 2021, approximately 55.5 percent of the air traffic liability balance was related to forward bookings, with the remaining 44.5 percent related to credit vouchers for future travel. The normal contract term of passenger tickets is 12 months and revenue associated with future travel will principally be recognized within this time frame. $70.2 million of the $307.5 million that was recorded in the air traffic liability balance as of December 31, 2020 was recognized into passenger revenue during the three months ended March 31, 2021. In 2020, the Company announced that credits issued for canceled travel beginning in January 2020 would have an extended expiration date of two years from the original booking date. This policy continues in effect at the current time. This change has been considered in estimating the future breakage rate, which represents the value of credit vouchers that are not expected to be redeemed prior to their contractual expiration date. Co-brand redemptions In relation to the travel component of the co-branded credit card contract with Bank of America, the Company has a performance obligation to provide cardholders with points to be used for future travel award redemptions. Therefore, consideration received from Bank of America related to the travel component is deferred based on its relative selling price and is recognized into passenger revenue when the points are redeemed and the transportation is provided. The following table presents the activity of the co-brand point liability for the periods indicated: Three Months Ended March 31, (in thousands) 2021 2020 Balance at January 1 $ 21,841 $ 15,613 Points awarded (deferral of revenue) 4,571 6,354 Points redeemed (recognition of revenue) (3,694) (4,686) Balance at March 31 $ 22,718 $ 17,281

Property and Equipment

Property and Equipment	3 Months Ended
	Mar. 31, 2021
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment Disclosure	Property and Equipment The following table summarizes the Company's property and equipment as of the dates indicated: (in thousands) March 31, 2021 December 31, 2020 Flight equipment, including pre-delivery deposits $ 2,370,269 $ 2,331,499 Computer hardware and software 151,755 149,727 Land and buildings/leasehold improvements (1) 87,030 87,030 Other property and equipment 80,672 80,601 Total property and equipment 2,689,726 2,648,857 Less accumulated depreciation and amortization (617,515) (598,546) Property and equipment, net $ 2,072,211 $ 2,050,311 (1) Balance includes a building currently held for sale in Chesterfield, Missouri with a carrying value of $4.3 million Accrued capital expenditures as of March 31, 2021 and December 31, 2020 were $4.1 million and $16.9 million, respectively.

Long-Term Debt

Long-Term Debt	3 Months Ended
	Mar. 31, 2021
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt The following table summarizes the Company's Long-term debt and finance lease obligations as of the dates indicated: (in thousands) March 31, 2021 December 31, 2020 Fixed-rate debt and finance lease obligations due through 2029 $ 619,874 $ 525,240 Variable-rate debt due through 2029 996,178 1,133,771 Total long-term debt and finance lease obligations, net of related costs 1,616,052 1,659,011 Less current maturities, net of related costs 156,482 217,234 Long-term debt and finance lease obligations, net of current maturities and related costs $ 1,459,570 $ 1,441,777 Weighted average fixed-interest rate on debt 5.8 % 5.7 % Weighted average variable-interest rate on debt 2.5 % 2.4 % Maturities of long-term debt and finance lease obligations for the remainder of 2021 and for the next four years and thereafter, in the aggregate, are: remaining in 2021 - $120.4 million; 2022 - $131.9 million; 2023 - $131.7 million; 2024 - $801.6 million; 2025 - $84.6 million; and $345.8 million thereafter. Senior Secured Revolving Credit Facility The senior secured revolving credit facility under which the Company was able to borrow up to $81.0 million matured on March 31, 2021. Principal payments were made during the quarter totaling $7.4 million and the final outstanding balance of $46.5 million was paid at maturity. In March 2021, the Company entered into a new revolving credit facility under which it is entitled to borrow up to $50.0 million. The facility has a term of 24 months and the borrowing ability is based on the value of the Airbus A320 series aircraft placed into the collateral pool. The notes for amounts borrowed under the facility bear interest at a floating rate based on LIBOR and are due in March 2023. As of March 31, 2021, no aircraft collateral had been added to the collateral pool and the facility was undrawn.

Income Taxes (Notes)

Income Taxes (Notes)	3 Months Ended
	Mar. 31, 2021
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Text Block]	Income TaxesThe Company recorded an effective tax rate of 20.8 percent and 74.7 percent for the three months ended March 31, 2021 and 2020, respectively. The effective tax rate for the three months ended March 31, 2021 differed from the statutory Federal income tax rate of 21.0 percent primarily due to state income taxes; the impact of ASU 2016-09 related to share-based payments; and reserve for uncertain tax positions. The effective tax rate for the three months ended March 31, 2020 was primarily due to the tax accounting impact of the CARES Act which includes a $39.6 million discrete federal income tax benefit related to the full utilization of 2018 and 2019 net operating losses against taxable income in earlier years in which 35.0 percent was the enacted tax rate; the ability to carryback the 2020 net operating loss at a 35.0 percent rate applicable in earlier years; a deferred tax remeasurement related to the 2020 tax year; and state taxes. While the Company expects its effective tax rate to be fairly consistent in the near term, it will vary depending on recurring items such as the amount of income earned in each state and the state tax rate applicable to such income. Discrete items during interim periods may also affect the Company's tax rates.

Leases (Notes)

Leases (Notes)	3 Months Ended
	Mar. 31, 2021
Leases [Abstract]
Lessee, Leases [Policy Text Block]	Leases The Company evaluates all operating leases and they are measured on the balance sheet with a lease liability and right-of-use asset (“ROU”) at inception. ROU assets represent the Company’s right to use an underlying asset for the lease term, and lease liabilities represent the obligation to make scheduled lease payments. Airport terminal leases mostly include variable lease payments outside of those based on a fixed index, and are therefore not recorded as ROU assets. The following table summarizes the Company's total assets and liabilities related to leases as of the dates indicated: (in thousands) Classification on the Balance Sheet March 31, 2021 December 31, 2020 Assets Operating lease assets (1) Operating lease right-of-use assets $ 116,998 $ 115,911 Finance lease assets (2) Property and equipment, net 242,280 133,175 Total lease assets $ 359,278 $ 249,086 Liabilities Current Operating (1) Current operating lease liabilities $ 15,247 $ 14,313 Finance (2) Current maturities of long-term debt and finance lease obligations 13,358 9,767 Noncurrent Operating (1) Noncurrent operating lease liabilities 103,103 102,289 Finance (2) Long-term debt and finance lease obligations 215,354 117,060 Total lease liabilities $ 347,062 $ 243,429 (1) Represents assets and liabilities of 13 aircraft, office equipment, certain airport and terminal facilities, and other assets under operating leases (2) March 31, 2021, number represents assets and liabilities of nine aircraft under finance leases Sale-Leaseback Transaction In March 2021, the Company entered into a sale-leaseback transaction involving three aircraft and generating $105.0 million of proceeds. The lease was classified as a finance lease and as a result, the transaction did not qualify as a sale. The aircraft were not removed from property and equipment in the Company's balance sheet and the Company recorded a financial liability in the amount of $105.0 million. The proceeds from this transaction are treated as cash inflows from finance lease obligations and reported in financing activities on the statement of cash flows.
Sale Leaseback Transactions [Text Block]	Sale-Leaseback Transaction In March 2021, the Company entered into a sale-leaseback transaction involving three aircraft and generating $105.0 million of proceeds. The lease was classified as a finance lease and as a result, the transaction did not qualify as a sale. The aircraft were not removed from property and equipment in the Company's balance sheet and the Company recorded a financial liability in the amount of $105.0 million. The proceeds from this transaction are treated as cash inflows from finance lease obligations and reported in financing activities on the statement of cash flows.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value, Measurement Inputs, Disclosure	Fair Value MeasurementsThe Company utilizes the market approach to measure the fair value of its financial assets. The market approach uses prices and other relevant information generated by market transactions involving identical or comparable assets. The assets classified as Level 2 primarily utilize quoted market prices or alternative pricing sources including transactions involving identical or comparable assets and models utilizing market observable inputs for valuation of these securities. No changes in valuation techniques or inputs occurred during the three months ended March 31, 2021. Financial instruments measured at fair value on a recurring basis: March 31, 2021 December 31, 2020 (in thousands) Total Level 1 Level 2 Total Level 1 Level 2 Cash equivalents Money market funds $ 160,730 $ 160,730 $ — $ 5,340 $ 5,340 $ — Municipal debt securities 59,417 — 59,417 34,338 — 34,338 Commercial Paper 21,889 — 21,889 48,908 — 48,908 Corporate debt securities 7,407 — 7,407 — — — Federal agency debt securities — — — 51,400 — 51,400 Total cash equivalents 249,443 160,730 88,713 139,986 5,340 134,646 Short-term Commercial paper 188,937 — 188,937 229,821 — 229,821 Corporate debt securities 115,812 — 115,812 166,768 — 166,768 Municipal debt securities 84,294 — 84,294 87,290 — 87,290 Federal agency debt securities 37,338 — 37,338 48,598 — 48,598 Total short-term 426,381 — 426,381 532,477 — 532,477 Total financial instruments $ 675,824 $ 160,730 $ 515,094 $ 672,463 $ 5,340 $ 667,123 None of the Company's debt is publicly held and as a result, the Company has determined the estimated fair value of these notes to be Level 3. Certain inputs used to determine fair value are unobservable and, therefore, could be sensitive to changes in inputs. The Company utilizes the discounted cash flow method to estimate the fair value of Level 3 debt. Carrying value and estimated fair value of long-term debt, including current maturities and without reduction for related costs, are as follows: March 31, 2021 December 31, 2020 (in thousands) Carrying Value Estimated Fair Value Carrying Value Estimated Fair Value Hierarchy Level Non-publicly held debt $ 1,408,823 $ 1,197,427 $ 1,555,637 $ 1,191,008 3 Due to their short-term nature, the carrying amounts of cash, cash equivalents, restricted cash, accounts receivable and accounts payable approximate fair value.

Earnings per Share

Earnings per Share	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Earnings per Share	Earnings (Loss) per Share Basic and diluted earnings (loss) per share are computed pursuant to the two-class method. Under this method, the Company attributes net income (loss) to two classes: common stock and unvested restricted stock. Unvested restricted stock awards granted to employees under the Company’s Long-Term Incentive Plan are considered participating securities as they receive non-forfeitable rights to cash dividends at the same rate as common stock. Diluted net income per share is calculated using the more dilutive of the two methods. Under both methods, the exercise of employee stock options is assumed using the treasury stock method. The assumption of vesting of restricted stock, however, differs: 1. Assume vesting of restricted stock using the treasury stock method. 2. Assume unvested restricted stock awards are not vested, and allocate earnings to common shares and unvested restricted stock awards using the two-class method. For the three months ended March 31, 2021, the second method was used because it was more dilutive than the first method. The following table sets forth the computation of net income (loss) per share, on a basic and diluted basis, for the periods indicated (share count and dollar amounts other than per-share amounts in the table are in thousands): Three Months Ended March 31, 2021 2020 Basic: Net income (loss) $ 6,869 $ (33,009) Less income allocated to participating securities (103) (236) Net income (loss) attributable to common stock $ 6,766 $ (33,245) Earnings (loss) per share, basic $ 0.42 $ (2.08) Weighted-average shares outstanding 16,167 15,952 Diluted: Net income (loss) $ 6,869 $ (33,009) Less income allocated to participating securities (103) (236) Net income (loss) attributable to common stock $ 6,766 $ (33,245) Earnings (loss) per share, diluted $ 0.42 $ (2.08) Weighted-average shares outstanding (1) 16,167 15,952 (1) Dilutive effect of common stock equivalents excluded from the diluted per share calculation is not material.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	ContingenciesThe Company is subject to certain legal and administrative actions it considers routine to its business activities. The Company believes the ultimate outcome of any potential and pending legal or administrative matters will not have a material adverse impact on its financial position, liquidity or results of operations.

Subsequent Events (Notes)

Subsequent Events (Notes)	3 Months Ended
	Mar. 31, 2021
Subsequent Event [Line Items]
Subsequent Events [Text Block]	Subsequent Events In April 2021, the Company received $13.8 million in funds related to the PSP2. In consideration for these additional funds, the Company issued additional warrants ( the "PSP2 Warrants") to the Treasury to acquire 924 shares of common stock at a price of $179.23 per share (based on the price of the Company's common stock on the Nasdaq Global Select Market.on December 24, 2020). Also, in consideration for these additional funds received, the PSP2 note was increased to $1.7 million. In April 2021, the Company through its airline operating subsidiary Allegiant Air, LLC entered into a Payroll Support Program 3 Agreement (the "PSP3") with the Treasury under section 7301 of the American Rescue Plan Act of 2021. The total amount expected to be allocated to Allegiant Air under the PSP3 is approximately $98.4 million, which must be used exclusively for wages, salaries and benefits. The Company received an initial installment of $49.2 million in April 2021 and the remainder of the funds are expected to be received during the second quarter 2021. If additional funds are allocated by the Treasury under the PSP3 such that the amount received by the Company exceeds $100.0 million, then Allegiant Air will issue a note for 30 percent for the funds received under the PSP3 in excess of $100.0 million and the Company will be required to issue warrants based on the amount of the notes. On April 30, 2021, the Company closed on a transaction to sell 85 percent of Teesnap, its golf course management software subsidiary. The Company will retain 15 percent ownership in the business.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies - (Policies)	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited consolidated financial statements include the accounts of Allegiant Travel Company (the “Company”) and its majority-owned operating subsidiaries. The Company's investments in unconsolidated affiliates, which are 50 percent or less owned, are accounted for under the equity or cost method, and are insignificant to the consolidated financial statements. All intercompany balances and transactions have been eliminated. These unaudited consolidated financial statements reflect all normal recurring adjustments which management believes are necessary to present fairly the financial position, results of operations, and cash flows of the Company for the respective periods presented. Certain information and footnote disclosures normally included in the annual consolidated financial statements prepared in accordance with U.S. generally accepted accounting principles ("U.S. GAAP") have been omitted pursuant to the rules and regulations of the Securities and Exchange Commission for Form 10-Q. These unaudited interim consolidated financial statements should be read in conjunction with the audited consolidated financial statements of the Company and notes thereto included in the annual report of the Company on Form 10-K for the year ended December 31, 2020 and filed with the Securities and Exchange Commission.
New Accounting Pronouncements	Recent Accounting PronouncementsOn December 18, 2019, the FASB issued ASU No. 2019-12, Simplifying the Accounting for Income Taxes. The standard simplifies the accounting and disclosure requirements for income taxes by clarifying existing guidance to improve consistency in application of Accounting Standards Codification ("ASC") 740. The standard also removes the requirement to calculate income tax expense for the stand-alone financial statements of wholly-owned subsidiaries. The standard is effective for fiscal years, and interim periods within those years, beginning after December 15, 2020, with early adoption permitted in any interim period within that year. The Company adopted this accounting standard prospectively as of January 1, 2021, and it did not have a significant impact on the Company's consolidated financial statements.

Leases, Codification Topic 842

Leases, Codification Topic 842 (Policies)	3 Months Ended
	Mar. 31, 2021
Leases [Abstract]
Lessee, Leases [Policy Text Block]	Leases The Company evaluates all operating leases and they are measured on the balance sheet with a lease liability and right-of-use asset (“ROU”) at inception. ROU assets represent the Company’s right to use an underlying asset for the lease term, and lease liabilities represent the obligation to make scheduled lease payments. Airport terminal leases mostly include variable lease payments outside of those based on a fixed index, and are therefore not recorded as ROU assets. The following table summarizes the Company's total assets and liabilities related to leases as of the dates indicated: (in thousands) Classification on the Balance Sheet March 31, 2021 December 31, 2020 Assets Operating lease assets (1) Operating lease right-of-use assets $ 116,998 $ 115,911 Finance lease assets (2) Property and equipment, net 242,280 133,175 Total lease assets $ 359,278 $ 249,086 Liabilities Current Operating (1) Current operating lease liabilities $ 15,247 $ 14,313 Finance (2) Current maturities of long-term debt and finance lease obligations 13,358 9,767 Noncurrent Operating (1) Noncurrent operating lease liabilities 103,103 102,289 Finance (2) Long-term debt and finance lease obligations 215,354 117,060 Total lease liabilities $ 347,062 $ 243,429 (1) Represents assets and liabilities of 13 aircraft, office equipment, certain airport and terminal facilities, and other assets under operating leases (2) March 31, 2021, number represents assets and liabilities of nine aircraft under finance leases Sale-Leaseback Transaction In March 2021, the Company entered into a sale-leaseback transaction involving three aircraft and generating $105.0 million of proceeds. The lease was classified as a finance lease and as a result, the transaction did not qualify as a sale. The aircraft were not removed from property and equipment in the Company's balance sheet and the Company recorded a financial liability in the amount of $105.0 million. The proceeds from this transaction are treated as cash inflows from finance lease obligations and reported in financing activities on the statement of cash flows.

COVID-19 (Tables)

COVID-19 (Tables)	3 Months Ended
	Mar. 31, 2021
Special Charge [Abstract]
Restructuring and Related Activities Disclosure [Text Block]	Special Charges The table below summarizes special charges recorded during the three months ended March 31, 2021. Three Months Ended March 31, (in thousands) 2021 2020 Operating $ 1,738 $ 166,098 Non-operating — 6,802 Total special charges $ 1,738 $ 172,900 Additional detail for the $1.7 million of total special charges for the three months ended March 31, 2021 appears below: • $1.2 million resulting from the accelerated retirements of two airframes and three engines • $0.5 million related to an impairment loss on a building in Chesterfield, Missouri associated with the Allegiant Nonstop family entertainment line of business. In the first quarter 2020, the onset of COVID-19 triggered an impairment review of long lived assets and a non-cash impairment charge of $163.4 million was recognized. The Company also identified $9.5 million of expenses, primarily comprised of salary and benefits, that were unique and specific to COVID-19.

Revenue Recognition (Tables)

Revenue Recognition (Tables)	3 Months Ended
	Mar. 31, 2021
Revenue Recognition [Abstract]
Disaggregation of Revenue [Table Text Block]	Three Months Ended March 31, (in thousands) 2021 2020 Scheduled service $ 131,929 $ 197,261 Ancillary air-related charges 121,072 176,964 Co-brand redemptions 3,694 4,686 Total passenger revenue $ 256,695 $ 378,911
Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block]	The following table presents the activity of the co-brand point liability for the periods indicated: Three Months Ended March 31, (in thousands) 2021 2020 Balance at January 1 $ 21,841 $ 15,613 Points awarded (deferral of revenue) 4,571 6,354 Points redeemed (recognition of revenue) (3,694) (4,686) Balance at March 31 $ 22,718 $ 17,281

Property and Equipment (Tables)

Property and Equipment (Tables)	3 Months Ended
	Mar. 31, 2021
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment	The following table summarizes the Company's property and equipment as of the dates indicated: (in thousands) March 31, 2021 December 31, 2020 Flight equipment, including pre-delivery deposits $ 2,370,269 $ 2,331,499 Computer hardware and software 151,755 149,727 Land and buildings/leasehold improvements (1) 87,030 87,030 Other property and equipment 80,672 80,601 Total property and equipment 2,689,726 2,648,857 Less accumulated depreciation and amortization (617,515) (598,546) Property and equipment, net $ 2,072,211 $ 2,050,311

Long-Term Debt (Tables)

Long-Term Debt (Tables)	3 Months Ended
	Mar. 31, 2021
Debt Disclosure [Abstract]
Summary of Long-Term Debt	The following table summarizes the Company's Long-term debt and finance lease obligations as of the dates indicated: (in thousands) March 31, 2021 December 31, 2020 Fixed-rate debt and finance lease obligations due through 2029 $ 619,874 $ 525,240 Variable-rate debt due through 2029 996,178 1,133,771 Total long-term debt and finance lease obligations, net of related costs 1,616,052 1,659,011 Less current maturities, net of related costs 156,482 217,234 Long-term debt and finance lease obligations, net of current maturities and related costs $ 1,459,570 $ 1,441,777 Weighted average fixed-interest rate on debt 5.8 % 5.7 % Weighted average variable-interest rate on debt 2.5 % 2.4 %

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2021
Leases [Abstract]
Leases of Lessee Disclosure [Text Block]	(in thousands) Classification on the Balance Sheet March 31, 2021 December 31, 2020 Assets Operating lease assets (1) Operating lease right-of-use assets $ 116,998 $ 115,911 Finance lease assets (2) Property and equipment, net 242,280 133,175 Total lease assets $ 359,278 $ 249,086 Liabilities Current Operating (1) Current operating lease liabilities $ 15,247 $ 14,313 Finance (2) Current maturities of long-term debt and finance lease obligations 13,358 9,767 Noncurrent Operating (1) Noncurrent operating lease liabilities 103,103 102,289 Finance (2) Long-term debt and finance lease obligations 215,354 117,060 Total lease liabilities $ 347,062 $ 243,429

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2021
Fair Value Disclosures [Abstract]
Assets Measured at Fair Value On a Recurring Basis	Financial instruments measured at fair value on a recurring basis: March 31, 2021 December 31, 2020 (in thousands) Total Level 1 Level 2 Total Level 1 Level 2 Cash equivalents Money market funds $ 160,730 $ 160,730 $ — $ 5,340 $ 5,340 $ — Municipal debt securities 59,417 — 59,417 34,338 — 34,338 Commercial Paper 21,889 — 21,889 48,908 — 48,908 Corporate debt securities 7,407 — 7,407 — — — Federal agency debt securities — — — 51,400 — 51,400 Total cash equivalents 249,443 160,730 88,713 139,986 5,340 134,646 Short-term Commercial paper 188,937 — 188,937 229,821 — 229,821 Corporate debt securities 115,812 — 115,812 166,768 — 166,768 Municipal debt securities 84,294 — 84,294 87,290 — 87,290 Federal agency debt securities 37,338 — 37,338 48,598 — 48,598 Total short-term 426,381 — 426,381 532,477 — 532,477 Total financial instruments $ 675,824 $ 160,730 $ 515,094 $ 672,463 $ 5,340 $ 667,123
Fair Value, Liabilities Measured on Recurring Basis	Carrying value and estimated fair value of long-term debt, including current maturities and without reduction for related costs, are as follows: March 31, 2021 December 31, 2020 (in thousands) Carrying Value Estimated Fair Value Carrying Value Estimated Fair Value Hierarchy Level Non-publicly held debt $ 1,408,823 $ 1,197,427 $ 1,555,637 $ 1,191,008 3

Earnings per Share (Tables)

Earnings per Share (Tables)	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Computation of Net Income Per Share, Basic and Diluted	The following table sets forth the computation of net income (loss) per share, on a basic and diluted basis, for the periods indicated (share count and dollar amounts other than per-share amounts in the table are in thousands): Three Months Ended March 31, 2021 2020 Basic: Net income (loss) $ 6,869 $ (33,009) Less income allocated to participating securities (103) (236) Net income (loss) attributable to common stock $ 6,766 $ (33,245) Earnings (loss) per share, basic $ 0.42 $ (2.08) Weighted-average shares outstanding 16,167 15,952 Diluted: Net income (loss) $ 6,869 $ (33,009) Less income allocated to participating securities (103) (236) Net income (loss) attributable to common stock $ 6,766 $ (33,245) Earnings (loss) per share, diluted $ 0.42 $ (2.08) Weighted-average shares outstanding (1) 16,167 15,952

COVID-19 COVID-19 (Details)

COVID-19 COVID-19 (Details) $ in Millions	3 Months Ended
	Mar. 31, 2021USD ($)number	Dec. 27, 2020USD ($)
Unusual or Infrequent Item, or Both [Line Items]
Total Proceeds To Be Provided to U.S. Airlines From Payroll Support Program Extension		$ 15,000
Payroll Support Program Grant Extension
Unusual or Infrequent Item, or Both [Line Items]
Number of Installments Received | number	2
Proceeds from Government Assistance, Payroll Support Program, CARES Act	$ 45.9
Total Proceeds from Payroll Support Program Grant	$ 91.8
COVID 19
Unusual or Infrequent Item, or Both [Line Items]
Unusual Or Infrequent Item, Reduction Of Salary	50.00%

COVID-19 COVID-19 Segment (Deta

COVID-19 COVID-19 Segment (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)Aircraftengine	Mar. 31, 2020USD ($)
Segment Reporting Information [Line Items]
Operating Special Charge, Total	$ 1,738	$ 166,098
Non-Operating Special Charge, Total	0	6,802
Special Charges	1,738	172,900
Asset Impairment Charges		163,400
Other Aircraft Related Costs	$ 1,200
Number of Engines Retired | engine	3
Other Expenses	$ 500
COVID 19
Segment Reporting Information [Line Items]
Operating Special Charge, Total		$ 9,500
Airbus A320 Aircraft Series
Segment Reporting Information [Line Items]
Number of Aircraft Retired | Aircraft	2

Revenue Recognition (Details)

Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 256,695	$ 378,911
Scheduled Service Revenue
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	131,929	197,261
Air-related revenue
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	121,072	176,964
Co-brand Revenue
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 3,694	$ 4,686

Revenue Recognition Passenger R

Revenue Recognition Passenger Revenue (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Apr. 30, 2020	Mar. 31, 2021	Dec. 31, 2020
Revenue Recognition [Abstract]
Contract with Customer, Liability, Forward Bookings		55.50%
Contract with Customer, Liability, Credit Voucher Bookings		44.50%
Revenue, Performance Obligation, Description of Timing		12 months
Contract with Customer, Liability, Current		$ 403,049	$ 307,508
Credit Voucher Term Expiration	2 years
Air Traffic Liability, Recognized		$ 70,200
Air Traffic Liability, Current			$ 307,500

Revenue Recognition Points Liab

Revenue Recognition Points Liability (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Points Liability [Abstract]
Contract with Customer, Liability	$ 22,718	$ 17,281	$ 21,841	$ 15,613
Points awarded	4,571	6,354
Points redeemed	(3,694)	(4,686)
Points Liability	$ 10,300	$ 12,500
Revenue, Performance Obligation, Description of Timing	12 months

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Flight equipment, including pre-delivery deposits	$ 2,370,269		$ 2,331,499
Computer hardware and software	151,755		149,727
Land and buildings/leasehold improvements (1)	87,030		87,030
Other property and equipment	80,672		80,601
Total property and equipment	2,689,726		2,648,857
Less accumulated depreciation and amortization	617,515		598,546
Property and equipment, net	2,072,211		2,050,311
Capital Expenditures Incurred but Not yet Paid	4,064	$ 46,452	$ 16,900
Building
Property, Plant and Equipment [Line Items]
Carrying Value of Asset Held for Sale, Building	$ 4,300

Long-Term Debt Components of Lo

Long-Term Debt Components of Long-Term Debt (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Secured Long-term Debt, Noncurrent	$ 1,616,052	$ 1,659,011
Less current maturities	156,482	217,234
Long-term debt and capital leases, net of current maturities and related costs	1,459,570	1,441,777
Senior Secured Revolving Credit Facility
Debt Instrument [Line Items]
Repayments of Lines of Credit	46,500
Weighted average fixed-interest rate on debt
Debt Instrument [Line Items]
Notes Payable	$ 619,874	$ 525,240
Long-term Debt, Weighted Average Interest Rate, at Point in Time	5.80%	5.70%
Weighted average variable-interest rate on debt
Debt Instrument [Line Items]
Notes Payable	$ 996,178	$ 1,133,771
Long-term Debt, Weighted Average Interest Rate, at Point in Time	2.50%	2.40%

Long-Term Debt Schedule of Matu

Long-Term Debt Schedule of Maturities of Long-Term Debt (Details) $ in Millions	Mar. 31, 2021USD ($)
Schedule of Maturities of Long-Term Debt [Abstract]
Long-Term Debt, Maturity, Remainder of Fiscal Year	$ 120.4
Long-Term Debt, Maturity, Year Two	131.9
Long-Term Debt, Maturity, Year Three	131.7
Long-Term Debt, Maturity, Year Four	801.6
Long-Term Debt, Maturity, Year Five	84.6
Long-Term Debt, Maturity, after Year Five	$ 345.8

Long-Term Debt (Details)

Long-Term Debt (Details) $ in Millions	1 Months Ended	3 Months Ended
	Sep. 30, 2020USD ($)	Mar. 31, 2021USD ($)Aircraft	Apr. 23, 2021USD ($)	Dec. 31, 2018USD ($)
Senior Secured Revolving Credit Facility
Debt Instrument, Term		24 months
Line of Credit Facility, Maximum Borrowing Capacity				$ 81
Number Of Aircrafts Included As Collateral | Aircraft		0
Line of Credit Facility, Periodic Payment, Principal	$ 7.4
Line of Credit Facility [Line Items]
Repayments of Lines of Credit		$ 46.5
Airbus A320 Aircraft Series | Senior Secured Revolving Credit Facility
Debt Instrument, Face Amount		$ 50
Subsequent Event
Debt Instrument, Face Amount			$ 1.7

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation, Percent	20.80%	74.70%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%
Discrete Income Tax Expense (Benefit)		$ 39,600
Effective Income Tax Rate Reconciliation,Other Reconciling Items, Percent		35.00%
Effective Income Tax Rate Reconciliation, Other Adjustments, Percent		35.00%

Leases (Details)

Leases (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)Aircraft	Dec. 31, 2020USD ($)
Leases [Abstract]
Operating Leased Assets, Number of Units | Aircraft	13
Finance Leased Assets, Number of Units | Aircraft	9
Number Of Aircraft In Sale-Leaseback Transactions | Aircraft	3
operating right of use asset, net	$ 116,998	$ 115,911
Finance Lease, Right-of-Use Asset, after Accumulated Amortization	242,280	133,175
Total Right-of-Use Asset	359,278	249,086
Current operating lease liabilities	15,247	14,313
Finance Lease, Liability, Current	13,358	9,767
Noncurrent operating lease liabilities	103,103	102,289
Finance Lease, Liability, Noncurrent	215,354	117,060
Total Lease Liability	347,062	$ 243,429
Sale Leaseback Transaction, Net Proceeds, Financing Activities	$ 105,000

Fair Value Measurements (Detail

Fair Value Measurements (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Available-for-sale Securities	$ 675,824	$ 672,463
Fair Value, Inputs, Level 1
Available-for-sale Securities	160,730	5,340
Fair Value, Inputs, Level 2
Available-for-sale Securities	515,094	667,123
Short-term Investments
Available-for-sale Securities	426,381	532,477
Short-term Investments | Fair Value, Inputs, Level 1
Available-for-sale Securities	0	0
Short-term Investments | Fair Value, Inputs, Level 2
Available-for-sale Securities	426,381	532,477
Short-term Investments | Commercial paper
Available-for-sale Securities	188,937	229,821
Short-term Investments | Commercial paper | Fair Value, Inputs, Level 1
Available-for-sale Securities	0	0
Short-term Investments | Commercial paper | Fair Value, Inputs, Level 2
Available-for-sale Securities	188,937	229,821
Short-term Investments | Municipal debt securities
Available-for-sale Securities	84,294	87,290
Short-term Investments | Municipal debt securities | Fair Value, Inputs, Level 1
Available-for-sale Securities	0	0
Short-term Investments | Municipal debt securities | Fair Value, Inputs, Level 2
Available-for-sale Securities	84,294	87,290
Short-term Investments | Corporate debt securities
Available-for-sale Securities	115,812	166,768
Short-term Investments | Corporate debt securities | Fair Value, Inputs, Level 1
Available-for-sale Securities	0	0
Short-term Investments | Corporate debt securities | Fair Value, Inputs, Level 2
Available-for-sale Securities	115,812	166,768
Short-term Investments | US Treasury Bond Securities
Available-for-sale Securities	37,338	48,598
Short-term Investments | US Treasury Bond Securities | Fair Value, Inputs, Level 1
Available-for-sale Securities	0	0
Short-term Investments | US Treasury Bond Securities | Fair Value, Inputs, Level 2
Available-for-sale Securities	37,338	48,598
Cash Equivalents
Cash Equivalents	249,443	139,986
Cash Equivalents | Fair Value, Inputs, Level 1
Cash Equivalents	160,730	5,340
Cash Equivalents | Fair Value, Inputs, Level 2
Cash Equivalents	88,713	134,646
Cash Equivalents | Money Market Funds
Cash Equivalents	160,730	5,340
Cash Equivalents | Money Market Funds | Fair Value, Inputs, Level 1
Cash Equivalents	160,730	5,340
Cash Equivalents | Money Market Funds | Fair Value, Inputs, Level 2
Cash Equivalents	0	0
Cash Equivalents | Commercial paper
Cash Equivalents	21,889	48,908
Cash Equivalents | Commercial paper | Fair Value, Inputs, Level 1
Cash Equivalents	0	0
Cash Equivalents | Commercial paper | Fair Value, Inputs, Level 2
Cash Equivalents	21,889	48,908
Cash Equivalents | Municipal debt securities
Cash Equivalents	59,417	34,338
Cash Equivalents | Municipal debt securities | Fair Value, Inputs, Level 1
Cash Equivalents	0	0
Cash Equivalents | Municipal debt securities | Fair Value, Inputs, Level 2
Cash Equivalents	59,417	34,338
Cash Equivalents | Federal agency debt securities
Cash Equivalents	0	51,400
Cash Equivalents | Federal agency debt securities | Fair Value, Inputs, Level 1
Cash Equivalents	0	0
Cash Equivalents | Federal agency debt securities | Fair Value, Inputs, Level 2
Cash Equivalents	0	51,400
Cash Equivalents | Corporate debt securities
Cash Equivalents	7,407	0
Cash Equivalents | Corporate debt securities | Fair Value, Inputs, Level 1
Cash Equivalents	0	0
Cash Equivalents | Corporate debt securities | Fair Value, Inputs, Level 2
Cash Equivalents	$ 7,407	$ 0

Fair Value Measurements Estimat

Fair Value Measurements Estimated Fair Value of Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	$ 1,616,052	$ 1,659,011
Non-Publicly Held Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Secured Long-term Debt, Noncurrent	1,408,823	1,555,637
Non-Publicly Held Debt | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	$ 1,197,427	$ 1,191,008

Earnings per Share (Details)

Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Basic:
Net income attributable to Allegiant Travel Company (in Dollars)	$ 6,869	$ (33,009)
Less: Net income allocated to participating securities (in Dollars)	(103)	(236)
Net income attributable to common stock (in Dollars)	$ 6,766	$ (33,245)
Net income per share, basic (in Dollars per share)	$ 0.42	$ (2.08)
Weighted-average shares outstanding	16,167	15,952
Undistributed Earnings (Loss) Allocated to Participating Securities, Diluted	$ (103)	$ (236)
Net Income (Loss) Available to Common Stockholders, Diluted	$ 6,766	$ (33,245)
Diluted earnings per share	$ 0.42	$ (2.08)

Operating Segments (Details)

Operating Segments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Segment Reporting Information [Line Items]
Asset Impairment Charges		$ 163,400
Revenue from Contract with Customer, Excluding Assessed Tax	$ 256,695	378,911
Third party products	13,622	15,976
Fixed fee contracts	7,692	8,919
Other	1,115	5,375
Operating Income (Loss)	24,602	(117,805)
Depreciation and amortization	43,174	$ 43,699
Assets	$ 3,345,200		$ 3,258,925

Impairment (Details)

Impairment (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020USD ($)
Segment Reporting Information [Line Items]
Asset Impairment Charges	$ 163.4

Subsequent Events (Details)

Subsequent Events (Details) - Subsequent Event - USD ($) $ / shares in Units, $ in Millions	Apr. 30, 2021	Apr. 23, 2021	Apr. 22, 2021	Dec. 24, 2020
Subsequent Event [Line Items]
Debt Instrument, Face Amount		$ 1.7
Equity Method Investment, Ownership Percentage	85.00%
Parent
Subsequent Event [Line Items]
Equity Method Investment, Ownership Percentage	15.00%
Payroll Support Program Grant Extension
Subsequent Event [Line Items]
Additional Proceeds Received from Payroll Support Program		$ 13.8
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		924
Class of Warrant or Right, Exercise Price of Warrants or Rights				$ 179.23
Payroll Support Program 3
Subsequent Event [Line Items]
Proceeds Expected From Payroll Support Program			$ 98.4
Proceeds Received From Payroll Support Program		$ 49.2
Debt Instrument, Amount Need To Exceed To Disburse Note		$ 100
Increase In Debt Instrument For Additional Installment		30.00%