Sky Harbour (SKYH) S-1/A 28 Apr 22 IPO registration (amended) Financial data

Document and Entity Information

Document and Entity Information	12 Months Ended
	Dec. 31, 2021
Cover [Abstract]
Document Type	S-1/A
Amendment Flag	false
Entity Registrant Name	Sky Harbour Group Corp
Entity Central Index Key	0001823587
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false

Balance Sheets

Balance Sheets - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash	$ 114,626	$ 1,122,194
Assets held in Trust	138,760,121	138,716,226
Prepaid expenses	239,660	403,186
Total Assets	139,114,407	140,241,606
Current liabilities:
Accounts payable and accrued expenses	1,174,980	153,928
Note payable to Sponsor	1,000,000	0
Deferred underwriting fee payable	4,759,615	4,759,615
Total current liabilities	6,934,595	4,913,543
Warrants liability	11,908,671	18,003,841
Total Liabilities	18,843,266	22,917,384
Commitments and Contingencies:
Stockholders' Equity:
Preferred stock, $0.0001 par value; 1,000,000 shares authorized; none issued and outstanding	0	0
Additional paid-in capital	0	0
Accumulated deficit	(18,437,959)	(21,384,878)
Total Stockholders' Equity	(18,437,619)	(21,384,538)
Total Liabilities and Stockholders' Equity	139,114,407	140,241,606
Common Class A [Member]
Current liabilities:
Class A common stock, $0.0001 par value; 13,598,898 shares subject to possible redemption at $10.20 per share	138,708,760	138,708,760
Stockholders' Equity:
Common stock	0	0
Common Class B [Member]
Stockholders' Equity:
Common stock	$ 340	$ 340

Balance Sheets (Parentheticals)

Balance Sheets (Parentheticals) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	1,000,000	1,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common Class A [Member]
Temporary equity, par value (in dollars per share)	$ 0.0001	$ 0.0001
Temporary equity, shares subject to possible redemption (in shares)	13,598,898	13,598,898
Temporary equity, redemption value per share (in dollars per share)	$ 10.20	$ 10.20
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common Class B [Member]
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	20,000,000	20,000,000
Common stock, shares issued (in shares)	3,399,724	3,399,724
Common stock, shares outstanding (in shares)	3,399,724	3,399,724

Statements of Operations

Statements of Operations - USD ($)	4 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2021
Professional fees and other expenses	$ (656,563)	$ (2,345,854)
State franchise taxes, other than income tax	(70,542)	(200,000)
General and administrative costs	(241,749)	(639,439)
Change in fair value of warrant liability	(2,070,328)	6,095,170
Net income (loss) income from operations	(3,039,182)	2,909,877
Other income - interest and dividend income	0	35,423
Gain on disposition of investments	12,297	0
Unrealized gain on marketable securities held in Trust	2,081	1,619
Income (loss) before income taxes	(3,024,804)	2,946,919
Income tax (provision) benefit	0	0
Net income (loss) attributable to common shares	$ (3,024,804)	$ 2,946,919
Common Class A [Member]
Net income (loss) per common share:
Class A common stock - basic and diluted (in dollars per share)	$ (0.27)	$ 0.17
Common Class B [Member]
Net income (loss) per common share:
Class A common stock - basic and diluted (in dollars per share)	$ (0.27)	$ 0.17

Statement of Changes in Stockho

Statement of Changes in Stockholders' Equity - USD ($)	IPO [Member]Common Stock [Member]Common Class A [Member]	IPO [Member]Common Stock [Member]Common Class B [Member]	IPO [Member]Additional Paid-in Capital [Member]	IPO [Member]Retained Earnings [Member]	IPO [Member]	Common Stock [Member]Common Class A [Member]	Common Stock [Member]Common Class B [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Total
Balance (in shares) at Aug. 24, 2020						0	0
Balance at Aug. 24, 2020						$ 0	$ 0	$ 0	$ 0	$ 0
Stock Issued During Period, Shares, New Issues (in shares)						0	3,593,750
Issuance of common stock	$ 0	$ 0	$ 135,988,980	$ 0	$ 135,988,980	$ 0	$ 359	24,641	0	25,000
Offering costs						$ 0	$ 0	(7,451,220)	0	(7,451,220)
Over-allotment reduction of Class B common stock (in shares)						0	(194,026)
Over-allotment reduction of Class B common stock						$ 0	$ (19)	19	0	0
Sale of private placement warrants to Sponsor						0	0	7,719,779	0	7,719,779
Reclassification of warrants to liabilities						0	0	(15,933,513)	0	(15,933,513)
Common stock subject to possible redemption						0	0	(120,348,686)	(18,360,074)	(138,708,760)
Net income (loss)						$ 0	$ 0	0	(3,024,804)	(3,024,804)
Balance (in shares) at Dec. 31, 2020						0	3,399,724
Balance at Dec. 31, 2020						$ 0	$ 340	0	(21,384,878)	(21,384,538)
Net income (loss)						$ 0	$ 0	0	2,946,919	2,946,919
Balance (in shares) at Dec. 31, 2021						0	3,399,724
Balance at Dec. 31, 2021						$ 0	$ 340	$ 0	$ (18,437,959)	$ (18,437,619)

Statements of Cash Flows

Statements of Cash Flows - USD ($)	4 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2021
Cash Flows from Operating Activities:
Net Income (Loss)	$ (3,024,804)	$ 2,946,919
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Unrealized gain on marketable securities held in Trust	(2,081)	(1,619)
Gain on disposition of investments	(12,297)	0
Issuance costs related to warrant liability	509,899	0
Change in fair value of warrant liability	2,070,328	(6,095,170)
Changes in operating assets and liabilities:
Prepaid expenses	(403,186)	163,526
Accounts payable and accrued expenses	153,928	1,021,052
Net cash used in operating activities	(708,213)	(1,965,292)
Cash Flows from Investing Activities:
Proceeds from sales of investments	266,000,000	1,179,227,029
Purchase of investments	(404,701,848)	(1,179,269,305)
Net cash used in investing activities	(138,701,848)	(42,276)
Cash Flows from Financing Activities:
Proceeds from issuance of Private Placement Warrants	7,719,779	0
Proceeds from note payable to Sponsor	0	1,000,000
Offering costs	(3,201,504)	0
Net cash provided by financing activities	140,532,255	1,000,000
Net (decrease) increase in cash	1,122,194	(1,007,568)
Cash - beginning of the period	0	1,122,194
Cash - end of the period	1,122,194	114,626
Interest Paid in Cash	0	0
Income Taxes Paid in Cash	0	0
Common Class A [Member]
Cash Flows from Financing Activities:
Proceeds from issuance of common stock	135,988,980	0
Common Class B [Member]
Cash Flows from Financing Activities:
Proceeds from issuance of common stock	$ 25,000	$ 0

Note 1 - Organization and Busin

Note 1 - Organization and Business Operations	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	1. Organization and Business Operations Organization and General Yellowstone Acquisition Company (the “Company”) was incorporated in Delaware on August 25, 2020. The Company was formed for the purpose of effecting a merger, capital stock exchange, asset acquisition, stock purchase, reorganization or similar Business Combination with one or more businesses (the “Business Combination”). The Company has neither engaged in any operations nor generated any revenue to date. The Company’s management has broad discretion with respect to the Business Combination, but intends to focus its search for a target business in the homebuilding, manufacturing serving the homebuilding market, financial services and commercial real estate industries. The Company’s Sponsor is BOC Yellowstone LLC, a Delaware limited liability company (the “Sponsor”). The Company has selected December 31 as its year-end. The Company completed its initial public offering (“IPO”) on October 26, 2020 as further described below. The Company will not generate any operating revenues until after the completion of its Business Combination, at the earliest. Subsequent to the IPO, the Company has generated and will continue to generate non-operating income in the form of investment income on cash and cash equivalents from the proceeds derived from the IPO and the sale of the Private Placement Warrants (as defined below) held in the Trust Account (as defined below). Sky Harbour Business Combination On August 1, 2021, Yellowstone Acquisition Company (the “Company”) and Sky Harbour LLC (“SHG”), a Delaware limited liability company, entered into a definitive equity purchase agreement (the “Equity Purchase Agreement”), which was subsequently announced on August 2, 2021. Immediately thereafter, BOC YAC Funding LLC (“BOC YAC”), a Delaware limited liability company and wholly owned subsidiary of Boston Omaha Corporation (“Boston Omaha”), entered into a Series B Preferred Unit Purchase Agreement (the “Series B Purchase Agreement”) with SHG, which was also subsequently announced. On August 25, 2021, SHG announced that its subsidiary, Sky Harbour Capital LLC (“SH Capital”), entered into an agreement for $166 million in financing through the sale of Series 2021 private activity tax-exempt senior bonds through municipal conduit issuer, Public Finance Authority (“PFA”). SH Capital and its subsidiaries Sky Harbour Sugar Land Airport, LLC, Sky Harbour Opa Locka Airport, LLC, Nashville Hangars LLC, APA Hangars LLC, and DVT Hangars LLC constitute an Obligated Group, the property and revenues of which secure the bonds on a joint and several basis. The bond issuance consists of unrated senior fixed rate tax-exempt bonds with three term maturities, in 2036, 2041 and 2054, with principal amortization from 2032 thru 2054 (average life of 24 years). The term bonds were priced to yield 3.80% (2036), 4.00% (2041) and 4.25% (2054). This bond financing was completed on September 14, 2021. On December 22, 2021, Boston Omaha Corporation, through its subsidiary BOC YAC, LLC, agreed to provide $45 million of PIPE financing through the purchase of Yellowstone Class A common stock at a price of $10.00 per share immediately prior to the closing of the business combination. In consideration of the investment, SHG agreed to waive the $150 million minimum financing condition which required that the Company deliver cash proceeds of at least $150 million (after payment of certain expenses) to SHG as a condition precedent to consummating the business combination. The Business Combination with SHG closed on January 25, 2022. The cash proceeds are expected to be used to fund the development of several new hangar campuses. Financing Upon the closing of the IPO, $127,500,000 ($10.20 per Unit) of the net proceeds of the sale of the units in the IPO, including proceeds of the sale of the Private Placement Warrants, were placed in a trust account (“Trust Account”) located in the United States at JP Morgan Chase Bank, N.A. with Continental Stock Transfer & Trust Company acting as trustee. In connection with the exercise of the underwriters’ overallotment option on December 1, 2020, $10,988,980 of the net proceeds of the sale of the additional units sold, inclusive of the proceeds from the sale of the additional Private Placement Warrants to our Sponsor, were placed in the Trust Account. Upon the closing of the Business Combination, the funds remaining in the Trust Account following were distributed to the Company. Trust Account Prior to the closing of the Business Combination, funds held in the Trust Account were invested in U.S. government securities, within the meaning set forth in Section 2(a)(16) of the Investment Company Act, with a maturity of 185 days or less, or in any open-ended investment company that holds itself out as a money market fund meeting certain conditions of Rule 2a-7 of the Investment Company Act, as determined by the Company. Business Combination The Company’s management had broad discretion with respect to the specific application of the net proceeds of the IPO and the sale of the Private Placement Warrants, although substantially all of the net proceeds were intended to be applied generally toward completing a Business Combination. The Company was required to complete its initial Business Combination with one or more target businesses that together have a fair market value equal to at least 80% of the net assets held in the Trust Account (excluding the amount of any deferred underwriting commissions held in the Trust Account) at the time of the agreement to enter into a Business Combination. The Company would have only completed a Business Combination if the post-Business Combination company owns or acquires 50% or more of the issued and outstanding voting securities of the target or otherwise acquires a controlling interest in the target business sufficient for it not to be required to register as an investment company under the Investment Company Act of 1940, as amended (the “Investment Company Act”). The Company, after signing a definitive agreement for a business combination, was required to provide its stockholders with the opportunity to redeem all or a portion of their Public Shares upon the completion of a Business Combination either (i) in connection with a stockholder meeting called to approve the Business Combination or (ii) by means of a tender offer. The stockholders were entitled to redeem their shares for a pro rata portion of the amount held in the Trust Account (initially $10.20 per share), calculated as of two business days prior to the completion of a Business Combination, including any pro rata interest earned on the funds held in the Trust Account and not previously released to the Company to pay its tax obligations. There are no redemption rights upon the completion of a Business Combination with respect to the Company’s warrants. The shares of Class A common stock are recorded at redemption value and classified as temporary equity, in accordance with Accounting Standards Codification (“ASC”) Topic 480 “Distinguishing Liabilities from Equity.” On January 25, 2022, the Company held a special meeting of the Company’s stockholders (the “Special Meeting”), held in lieu of the 2021 annual meeting of the Company’s stockholders, at which stockholders representing a majority of the outstanding shares of common stock approved the SHG business combination. The actual redemptions of common stock by Company stockholders in conjunction with the stockholder vote was 12,061,041 shares. Emerging Growth Company The Company is an “emerging growth company,” as defined in Section 2(a) of the Securities Act, as modified by the Jumpstart our Business Startups Act of 2012 (the “JOBS Act”), and it has opted to take advantage of certain exemptions from various reporting requirements that are applicable to other public companies that are not emerging growth companies including, but not limited to, not being required to comply with the auditor attestation requirements of Section 404 of the Sarbanes-Oxley Act reduced disclosure obligations regarding executive compensation in its periodic reports and proxy statements, and exemptions from the requirements of holding a nonbinding advisory vote on executive compensation and stockholder approval of any golden parachute payments not previously approved. Further, section 102(b)(1) of the JOBS Act exempts emerging growth companies from being required to comply with new or revised financial accounting standards until private companies (that is, those that have not had a Securities Act registration statement declared effective or do not have a class of securities registered under the Exchange Act are required to comply with the new or revised financial accounting standards. The JOBS Act provides that an emerging growth company can elect to opt out of the extended transition period and comply with the requirements that apply to non-emerging growth companies but any such election to opt out is irrevocable. The Company has not elected to opt out of such extended transition period, which means that when a standard is issued or revised and it has different application dates for public or private companies, the Company, as an emerging growth company, will adopt the new or revised standard at the time private companies adopt the new or revised standard. This may make comparison of the Company’s financial statement with another emerging growth company which has opted out of using the extended transition period difficult or impossible because of the potential differences in accounting standards used.

Note 2 - Significant Accounting

Note 2 - Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Significant Accounting Policies [Text Block]	2. Significant Accounting Policies Basis of Presentation The accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and pursuant to the accounting and disclosure rules and regulations of the Securities and Exchange Commission. Net Loss Per Common Share Net (loss) income per share of common stock is computed by dividing net (loss) income by the weighted average number of common shares outstanding during the period. We apply the two-class method in calculating earnings per share. Accretion associated with the redeemable shares of Class A common stock is excluded from earnings per share as the redemption value approximates fair value. As of December 31, 2021 and December 31, 2020, we had outstanding warrants to purchase up to 14,519,228 shares of Class A common stock. The weighted average of these shares was excluded from the calculation of diluted net (loss) income per share of common stock since the exercise of the warrants is contingent upon the occurrence of future events. As of December 31, 2021, we did not have any dilutive securities or other contracts that could, potentially, be exercised or converted into shares of common stock and then share in our earnings. As a result, diluted net (loss) income per common share is the same as basic net (loss) income per common share for the periods presented. Reconciliation of Net Earnings (Loss) per common share Basic and diluted loss per common share is calculated as follows: ​ ​ For the Year Ended December 31, 2021 ​ ​ For the Period from August 25, 2020 (inception) through December 31, 2020 ​ ​ Class A ​ ​ Class B ​ ​ Class A ​ ​ Class B Basic and diluted net income (loss) per share ​ ​ ​ ​ ​ ​ ​ ​ Numerator: ​ ​ ​ ​ ​ ​ ​ ​ Allocation of net income (loss) ​ ​ $ 2,357,536 ​ ​ $ 589,383 ​ ​ $(1,868,311) ​ ​ $(1,156,493) ​ ​ ​ ​ ​ ​ ​ ​ Denominator: ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average shares outstanding ​ ​ 13,598,898 ​ ​ 3,399,724 ​ ​ 6,975,341 ​ ​ 4,317,769 ​ ​ ​ ​ ​ ​ ​ ​ Basic and diluted net income (loss) per share ​ ​ $ 0.17 ​ ​ $ 0.17 ​ ​ $ (0.27) ​ ​ $ (0.27) Cash and Cash Equivalents The Company considers all highly liquid instruments purchased with an original maturity of three Concentration of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist of cash accounts in a financial institution, which, at times, may exceed the Federal Depository Insurance Coverage of $250,000. At December 31, 2021, the Company has not experienced losses on these accounts and management believes the Company is not exposed to significant risks on such accounts. Financial Instruments The fair value of the Company’s assets and liabilities, which qualify as financial instruments under Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 820, “Fair Value Measurements and Disclosures,” approximates the carrying amounts presented in the balance sheet. Warrants Liability We account for the warrants in accordance with the guidance contained in Accounting Standards Codification 815 (“ASC 815”), “Derivatives and Hedging”, under which the warrants do not meet the criteria for equity treatment and must be recorded as derivative liabilities. Accordingly, we classify the warrants as liabilities at their fair value and adjust the warrants to fair value at each reporting period. This liability is subject to re-measurement at each balance sheet date until the warrants are exercised, and any change in fair value is recognized in our statement of operations. The fair value of the Private Placement Warrants and the Public Warrants issued in connection with the Public Offering have been measured based on the listed market price of such Warrants. Income Taxes The Company follows the asset and liability method of accounting for income taxes under ASC 740, “Income Taxes.” Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statements carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. Valuation allowances are established, when necessary, to reduce deferred tax assets to the amount expected to be realized. For those liabilities or benefits to be recognized, a tax position must be more-likely-than-not to be sustained upon examination by taxing authorities. The Company recognizes accrued interest and penalties related to uncertain tax positions as income tax expense. At December 31, 2021, management has not identified any uncertain tax positions that are not more likely than not to be sustained. The Company may be subject to potential examination by U.S. federal, states or foreign jurisdiction authorities in the areas of income taxes. These potential examinations may include questioning the timing and amount of deductions, the nexus of income amounts in various tax jurisdictions and compliance with U.S. federal, states or foreign tax laws. The Company is incorporated in the State of Delaware and is required to pay franchise taxes to the State of Delaware on an annual basis. Redeemable Shares of Class A Common Stock All of the 13,598,898 shares of Class A common stock sold as parts of the Units in the Public Offering contain a redemption feature. In accordance with the Accounting Standards Codification 480-10-S99-3A (“ASC 480”), “Classification and Measurement of Redeemable Securities”, redemption provisions not solely within the control of the Company require the security to be classified outside of permanent equity. Ordinary liquidation events, which involve the redemption and liquidation of all of the entity’s equity instruments, are excluded from the provisions of ASC 480. The Company classifies all shares of Class A common stock as redeemable. Recently issued accounting pronouncements not yet adopted Management does not not

Note 3 - Initial Public Offerin

Note 3 - Initial Public Offering	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Stockholders' Equity Note Disclosure [Text Block]	6. Stockholders’ Equity Common Stock Class A common stock — The Company is authorized to issue 200,000,000 shares of Class A common stock with a par value of $0.0001 per share. As of Class B common stock — The Company is authorized to issue 20,000,000 shares of Class B common stock with a par value of $0.0001 per share. As of Common stockholders of record are entitled to one vote for each share held on all matters to be voted on by stockholders. Holders of the Class A common stock and holders of the Class B common stock will vote together as a single class on all matters submitted to a vote of the Company’s stockholders, except as required by law. The shares of Class B common stock are identical to the shares of Class A common stock included in the units sold in the offering, and holders of Class B common stock have the same stockholder rights as public stockholders, except that (i) the shares of Class B common stock are subject to certain transfer restrictions, as described in more detail below, (ii) the Sponsor, officers and directors have entered into a letter agreement with the Company, pursuant to which they have agreed (A) to waive their redemption rights with respect to any Class B common stock and any public shares held by them in connection with the completion of the Business Combination and (B) to waive their rights to liquidating distributions from the Trust Account with respect to any Class B common stock held by them if the Company fails to complete the Business Combination within the prescribed time period, although they will be entitled to liquidating distributions from the Trust Account with respect to any public shares they hold if the Company fails to complete the Business Combination within such time period, (iii) the Class B common stock are shares that will automatically convert into shares of the Class A common stock at the time of the initial Business Combination, on a one-for-one basis, subject to adjustment pursuant to certain anti-dilution rights and (iv) are subject to registration rights. If the Company submits the Business Combination to the public stockholders for a vote, the Sponsor has agreed to vote any Class B common stock held by it and any public shares purchased during or after the offering in favor of the initial Business Combination. With certain limited exceptions, the shares of Class B common stock are not transferable, assignable or saleable (except to the officers and directors and other persons or entities affiliated with the Sponsor and other permitted transferees, each of whom will be subject to the same transfer restrictions) until the earlier of (A) one year after the completion of the initial Business Combination or (B) subsequent to the initial Business Combination, (x) if the last sale price of the Class A common stock equals or exceeds $12.00 per share (as adjusted for stock splits, stock dividends, reorganizations, recapitalizations and the like) for any 20 trading days within any 30-trading day period commencing at least 150 days after the initial Business Combination, or (y) the date on which the Company completes a liquidation, merger, capital stock exchange, reorganization or other similar transaction that results in all of the stockholders having the right to exchange their shares of common stock for cash, securities or other property. On November 16, 2020, BOC Yellowstone LLC transferred to BOC Yellowstone II LLC 206,250 shares of Class B common stock for no consideration. All other shares of Class B common stock are owned by BOC Yellowstone LLC. BOC Yellowstone LLC sold to the lead investor in the Company’s IPO a membership interest in BOC Yellowstone II LLC for a purchase price of $309,375. Upon the completion of any Business Combination, BOC Yellowstone LLC has agreed to transfer the 206,250 shares of Class B common stock to this investor. Any Class B common stock ultimately distributed to the investor is subject to all restrictions imposed on the Sponsor, including but not limited to, waiver of redemption rights in connection with completion of any initial Business Combination and rights to liquidating distributions from the trust account if the Company fails to complete the initial Business Combination. Any shares held by such investor will be subject to the anti-dilution provisions for the Class B common stock and the impact thereof. BOC Yellowstone LLC is the sole managing member of BOC Yellowstone II LLC. Preferred Stock The Company is authorized to issue 1,000,000 shares of preferred stock, with such designations, voting and other rights and preferences as may be determined from time to time by the Company’s board of directors. As of December 31, 2021, there were no shares of preferred stock issued or outstanding.
IPO [Member]
Notes to Financial Statements
Stockholders' Equity Note Disclosure [Text Block]	3. Initial Public Offering Public Units On October 26, 2020, the Company consummated its IPO of 12,500,000 units at $10.00 per Unit, generating gross proceeds of $125,000,000. Each unit issued in the offering consisted of one share of Yellowstone’s Class A common stock and one

Note 4 - Related Party Transact

Note 4 - Related Party Transactions	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Related Party Transactions Disclosure [Text Block]	4. Related Party Transactions Founder Shares On August 31, 2020, the Sponsor purchased 5,750,000 shares (the “Founder Shares”) of the Company’s Class B common stock, par value $0.0001 per share (the “Class B common stock”), for an aggregate price of $25,000. Between October 9, 2020, and December 31, 2020, the Sponsor surrendered 2,350,276 Founder Shares to the Company for no consideration, resulting in an aggregate of 3,399,724 Founder Shares outstanding as of December 31, 2021 and December 31, 2020. The Founder Shares will automatically convert into Class A common stock on a one-for-one basis at the time of the Company’s initial Business Combination and are subject to certain transfer restrictions. The sale of the Founders Shares is in the scope of ASC Topic 718, “Compensation-Stock Compensation.” Under ASC Topic 718, stock-based compensation associated with equity-classified awards is measured at fair value upon the grant date. The Founders Shares were granted subject to a performance condition (i.e., the occurrence of a Business Combination). Compensation expense related to the Founders Shares is recognized only when the performance condition is probable of occurrence. Stock-based compensation would be recognized at the consummation of a Business Combination in an amount equal to the number of Founders Shares that ultimately vest multiplied times the grant date fair value per share (unless subsequently modified) less the amount initially received for the purchase of the Founders Shares. Private Placement Warrants The Sponsor purchased an aggregate of 7,500,000 Private Placement Warrants at a price of $1.00 per Private Placement Warrant from the Company in a private placement that closed simultaneously with the closing of the IPO. In connection with the underwriter’s exercise of the over-allotment option on December 1, 2020, the Sponsor purchased an additional 219,779 private placement warrants at a price of $1.00 per whole warrant. Each Private Placement Warrant is exercisable for one share of Class A common stock at a price of $11.50 per share, subject to adjustment (see Note 6). Of the total $7,500,000 in initial proceeds from the sale of the Private Placement Warrants, $5,000,000 was added to the net proceeds from the IPO held in the Trust Account. If the Company does not complete a Business Combination within the Combination Period, the proceeds from the sale of the Private Placement Warrants held in the Trust Account will be used to fund the redemption of the Public Shares (subject to the requirements of applicable law) and the Private Placement Warrants will expire worthless. Related Party Reimbursement and Loans In addition, in order to finance transaction costs in connection with a Business Combination, the Sponsor or an affiliate of the Sponsor, or certain of the Company’s officers and directors may, but are not obligated to, loan the Company funds as may be required (“Working Capital Loans”). Any Working Capital Loans made by the Sponsor may be converted into warrants, at the price of $1.50 per warrant at the option of the lender. Such warrants would be identical to the Private Placement Warrants, including as to exercise price, exercisability and exercise period. If the Company completes a Business Combination, the Company would repay the Working Capital Loans out of the proceeds held in the Trust Account released to the Company. Otherwise, the Working Capital Loans would be repaid only out of funds held outside the Trust Account. In the event that a Business Combination is not completed, the Company may use a portion of the proceeds held outside the Trust Account to repay the Working Capital Loans but no proceeds held in the Trust Account would be used to repay the Working Capital Loans. On September 27, 2021, the Sponsor agreed to loan the Company an aggregate of up to $1,000,000 to cover expenses related to the Proposed Business Combination pursuant to a promissory note (the “Note”). This loan bears interest at the Federal Short Term Rate published pursuant to Section 1274(d) of the Internal Revenue Code, compounded annually. The loan is payable on the earlier of the date on which the Company consummates its Business Combination or the date that the Company’s winding up is effective. The principal balance, together with all accrued interest thereon, may be prepaid at any time at the election of the Company. As of December 31, 2021, there was $1,000,000 outstanding under the Note. The Sponsor may elect to convert all or any portion of the unpaid principal balance of the Note, together with all accrued and unpaid interest thereon, into that number of warrants, each whole warrant exercisable for one ordinary share of the Company (the “Conversion Warrants”), equal to: (x) the portion of the principal amount of the Note, together with all accrued and unpaid interest thereon, being converted, divided by (y) $1.50, rounded up to the nearest whole number of warrants.

Note 5 - Income Taxes

Note 5 - Income Taxes	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Income Tax Disclosure [Text Block]	5. Income Taxes Effective Tax Rate Reconciliation We are subject to taxation in all jurisdictions in which we operate that impose an income tax on our business activities. The components of the income tax expense for the years ended December 31, and the tax effects of temporary differences that give rise to deferred taxes at December 31, are as follows: ​ ​ Year ended December 31, ​ ​ 2021 ​ ​ 2020 Income tax expense (benefit): ​ ​ ​ ​ Deferred federal income tax expense (benefit) ​ ​ (767,176) ​ ​ (93,745) Deferred state income tax expense (benefit) ​ ​ (225,399) ​ ​ (32,634) ​ ​ ​ ​ Total Income Tax Benefit Before Valuation Allowance ​ ​ (992,575) ​ ​ (126,379) ​ ​ ​ ​ Valuation allowance ​ ​ 992,575 ​ ​ 126,379 ​ ​ ​ ​ Total Income Tax Expense (Benefit) ​ ​ $ — ​ ​ $ — A reconciliation of the statutory federal income tax expense to the income tax expense (benefit) from continuing operations provided at December 31, 2021 and December 31, 2020 is as follows: ​ ​ For the Year Ended December 31, 2021 ​ ​ For the Period from August 25, 2020 (inception) through December 31, 2020 Income tax expense (benefit) at the federal statutory rate ​ ​ $ 618,853 ​ ​ $ (93,745) State income taxes (benefit) - net of federal income tax benefits ​ ​ 182,709 ​ ​ (32,634) Unrealized gain on warrants ​ ​ (1,657,887) ​ ​ — Unrealized gain on securities ​ ​ (440) ​ ​ — Other, net ​ ​ (9,431) ​ ​ — Change in valuation allowance ​ ​ 866,196 ​ ​ 126,379 Total income tax expense (benefit) ​ ​ $ — ​ ​ $ — Components of the Company’s deferred tax assets at December 31, 2021 December 31, 2020 Net operating loss carryforwards ​ ​ $ 455,199 ​ ​ $ 126,379 Start-up costs ​ ​ 537,376 ​ ​ — Valuation allowance ​ ​ (992,575) ​ ​ (126,379) Total deferred tax asset ​ ​ $ — ​ ​ $ — The realization of deferred tax assets, including net operating loss carryforwards, is dependent on the generation of future taxable income sufficient to realize the tax deductions, carryforwards, and credits. Valuation allowances on deferred tax assets are recognized if it is determined that it is more likely than not that the asset will not be realized. For the years ended December 31, 2021 and 2020, we recorded a full valuation allowance due to historical losses before income taxes which reduced management’s ability to rely on future expectations of income. As of December 31, 2021, we have available federal tax operating loss carry forwards of approximately $1.7 million, which arose in tax years 2021 and 2020. Tax operating loss carryovers arising in years after 2017 may be carried forward indefinitely but are only available to offset 80% of future taxable income. We have available state tax operating loss carryforwards of approximately $1.7 million, which are available to reduce future state taxable income and would begin to expire in tax year 2040 in various amounts. Uncertain Tax Positions We believe that there are no tax positions taken or expected to be taken that would significantly increase or decrease unrecognized tax benefits within 12 months of the reporting date. The federal and state statutes of limitation for assessment of tax liability generally lapse within three years after the date the tax returns are filed. However, income tax attributes that are carried forward, such as net operating loss carryforwards, may be challenged and adjusted by taxing authorities at any time prior to the expiration of the statute of limitations for the tax year in which they are utilized. As of December 31, 2021, we do not have any open exams; however, all tax years are subject to examination by the Internal Revenue Service.

Note 6 - Stockholders' Equity

Note 6 - Stockholders' Equity	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Stockholders' Equity Note Disclosure [Text Block]	6. Stockholders’ Equity Common Stock Class A common stock — The Company is authorized to issue 200,000,000 shares of Class A common stock with a par value of $0.0001 per share. As of Class B common stock — The Company is authorized to issue 20,000,000 shares of Class B common stock with a par value of $0.0001 per share. As of Common stockholders of record are entitled to one vote for each share held on all matters to be voted on by stockholders. Holders of the Class A common stock and holders of the Class B common stock will vote together as a single class on all matters submitted to a vote of the Company’s stockholders, except as required by law. The shares of Class B common stock are identical to the shares of Class A common stock included in the units sold in the offering, and holders of Class B common stock have the same stockholder rights as public stockholders, except that (i) the shares of Class B common stock are subject to certain transfer restrictions, as described in more detail below, (ii) the Sponsor, officers and directors have entered into a letter agreement with the Company, pursuant to which they have agreed (A) to waive their redemption rights with respect to any Class B common stock and any public shares held by them in connection with the completion of the Business Combination and (B) to waive their rights to liquidating distributions from the Trust Account with respect to any Class B common stock held by them if the Company fails to complete the Business Combination within the prescribed time period, although they will be entitled to liquidating distributions from the Trust Account with respect to any public shares they hold if the Company fails to complete the Business Combination within such time period, (iii) the Class B common stock are shares that will automatically convert into shares of the Class A common stock at the time of the initial Business Combination, on a one-for-one basis, subject to adjustment pursuant to certain anti-dilution rights and (iv) are subject to registration rights. If the Company submits the Business Combination to the public stockholders for a vote, the Sponsor has agreed to vote any Class B common stock held by it and any public shares purchased during or after the offering in favor of the initial Business Combination. With certain limited exceptions, the shares of Class B common stock are not transferable, assignable or saleable (except to the officers and directors and other persons or entities affiliated with the Sponsor and other permitted transferees, each of whom will be subject to the same transfer restrictions) until the earlier of (A) one year after the completion of the initial Business Combination or (B) subsequent to the initial Business Combination, (x) if the last sale price of the Class A common stock equals or exceeds $12.00 per share (as adjusted for stock splits, stock dividends, reorganizations, recapitalizations and the like) for any 20 trading days within any 30-trading day period commencing at least 150 days after the initial Business Combination, or (y) the date on which the Company completes a liquidation, merger, capital stock exchange, reorganization or other similar transaction that results in all of the stockholders having the right to exchange their shares of common stock for cash, securities or other property. On November 16, 2020, BOC Yellowstone LLC transferred to BOC Yellowstone II LLC 206,250 shares of Class B common stock for no consideration. All other shares of Class B common stock are owned by BOC Yellowstone LLC. BOC Yellowstone LLC sold to the lead investor in the Company’s IPO a membership interest in BOC Yellowstone II LLC for a purchase price of $309,375. Upon the completion of any Business Combination, BOC Yellowstone LLC has agreed to transfer the 206,250 shares of Class B common stock to this investor. Any Class B common stock ultimately distributed to the investor is subject to all restrictions imposed on the Sponsor, including but not limited to, waiver of redemption rights in connection with completion of any initial Business Combination and rights to liquidating distributions from the trust account if the Company fails to complete the initial Business Combination. Any shares held by such investor will be subject to the anti-dilution provisions for the Class B common stock and the impact thereof. BOC Yellowstone LLC is the sole managing member of BOC Yellowstone II LLC. Preferred Stock The Company is authorized to issue 1,000,000 shares of preferred stock, with such designations, voting and other rights and preferences as may be determined from time to time by the Company’s board of directors. As of December 31, 2021, there were no shares of preferred stock issued or outstanding.

Note 7 - Commitments

Note 7 - Commitments	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Commitments and Contingencies Disclosure [Text Block]	7. Commitments Registration Rights The holders of the Founder Shares, Private Placement Warrants, Conversion Warrants that may be issued upon conversion of the Note, and any additional warrants that may be issued in connection with any further Working Capital Loans (and any shares of Class A common stock issuable upon the exercise of the Private Placement Warrants, the Conversion Warrants that may be issued upon conversion of the Note and any additional warrants that may be issued in connection with any further Working Capital Loans and upon conversion of the Founder Shares) will be entitled to registration rights pursuant to a registration rights agreement. The holders of these securities will be entitled to make up to three demands, excluding short form demands, that the Company register such securities. In addition, the holders have certain “piggy-back” registration rights with respect to registration statements filed subsequent to the completion of a Business Combination. However, the registration rights agreement provides that the Company will not permit any registration statement filed under the Securities Act to become effective until termination of the applicable lockup period. The Company will bear the expenses incurred in connection with the filing of any such registration statements. Underwriting Agreement The underwriters were entitled to a cash underwriting discount of $0.20 per Unit, or $2,500,000 in the aggregate, which amount was paid upon the closing of the Initial Public Offering. In addition, the underwriters are entitled to a deferred fee of $0.35 per Unit, or $4,759,615 (including over-allotment units) in the aggregate. The deferred fee will become payable to the underwriters from the amounts held in the Trust Account solely in the event that the Company completes a Business Combination, subject to the terms of the underwriting agreement.

Note 8 - Fair Value Measurement

Note 8 - Fair Value Measurements	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Fair Value Disclosures [Text Block]	8. Fair Value Measurements The Company follows the guidance in ASC 820 for its financial assets and liabilities that are re-measured and reported at fair value at each reporting period, and non-financial assets and liabilities that are re-measured and reported at fair value at least annually. The fair value of the Company’s financial assets and liabilities reflects management’s estimate of amounts that the Company would have received in connection with the sale of the assets or paid in connection with the transfer of the liabilities in an orderly transaction between market participants at the measurement date. In connection with measuring the fair value of its assets and liabilities, the Company seeks to maximize the use of observable inputs (market data obtained from independent sources) and to minimize the use of unobservable inputs (internal assumptions about how market participants would price assets and liabilities). The following fair value hierarchy is used to classify assets and liabilities based on the observable inputs and unobservable inputs used in order to value the assets and liabilities: Level 1: Quoted prices in active markets for identical assets or liabilities. An active market for an asset or liability is a market in which transactions for the asset or liability occur with sufficient frequency and volume to provide pricing information on an ongoing basis. Level 2: Observable inputs other than Level 1 inputs. Examples of Level 2 inputs include quoted prices in active markets for similar assets or liabilities and quoted prices for identical assets or liabilities in markets that are not active. Level 3: Unobservable inputs based on our assessment of the assumptions that market participants would use in pricing the asset or liability. The Company’s assets that are measured at fair value on a recurring basis at December 31, 2021 are comprised of $69,378,000 of marketable U.S. treasury securities and $69,382,121 of money market funds, both of which are held in the Trust Account, and $11,908,671 of Public and Private Placement warrants issued in connection with our Initial Public Offering, all of which are classified as Level 1 within the fair value hierarchy and are measured using quoted prices in active markets for identical assets or liabilities. For the year ended December 31, 2021, the Company recognized a gain in the statement of operations resulting from a decrease in the fair value of the warrant liability of $6,095,170 presented as change in fair value of warrant liability.

Note 9 - Subsequent Events

Note 9 - Subsequent Events	12 Months Ended
	Dec. 31, 2021
Notes to Financial Statements
Subsequent Events [Text Block]	9. Subsequent Events Business Combination with Sky As described in Note 1, the Company completed the business combination with Sky on January 25, 2022, following stockholder approval. Prior to the completion of the business combination, the Company entered into subscription agreements with BOC YAC, LLC, a subsidiary of Boston Omaha Corporation, pursuant to which the Company issued 4,500,000 shares of Class A common stock at $10 per share, for gross proceeds to the Company of $45,000,000, immediately prior to the completion of the business combination. Following this transaction, Sky became a consolidated subsidiary of the Company, which was renamed Sky Harbour Group Corporation, shares of which listed for trading on the New York Stock Exchange under the symbol “SKYH” on January 25, 2022. The Company’s financial statement presentation to be included in quarterly and annual filings with the SEC on Forms 10-Q and 10-K with respect to periods subsequent to the business combination with Sky will include the consolidated financial statements of Sky and its subsidiaries for periods prior to the completion of the Business Combination and of the Company for periods from and after the Business Combination. The Company paid the deferred underwriting discount totaling $4,759,615 or 3.50% of the gross offering proceeds of the Public Offering which was accrued as of December 31, 2021, to the underwriter on January 25, 2022 upon the Company’s consummation of the business combination with Sky. Also in connection with the closing of the business combination on January 25, 2022, the Company repaid the outstanding note payable to Sponsor of $1,000,000 in full. OPF Lease Transaction The Company’s ground lease at OPF was entered into in May 2019 through its wholly owned subsidiary, Sky Harbour Opa Locka Airport LLC (“SHOLA”), with AA Acquisitions LLC (“AA”), the master ground lessee of Miami Dade County (“MDC”), the ultimate landowner. On March 2, 2022, the Company, through a wholly-owned subsidiary outside the Obligated Group, entered into an agreement for the Company to purchase AA’s underlying ground lease for approximately $8.5 million and lease the OPF property directly from MDC. The transaction will also require the Company to pay approximately $1.0 million in transfer fees to MDC and is expected to close in early April 2022. After such closing, SHOLA will continue to be obligated under the existing sublease but to an affiliate within the Company. The transaction would extend the term of the lease at OPF for the Company for an additional 10 years.

Significant Accounting Policies

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	Basis of Presentation The accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and pursuant to the accounting and disclosure rules and regulations of the Securities and Exchange Commission.
Earnings Per Share, Policy [Policy Text Block]	Net Loss Per Common Share Net (loss) income per share of common stock is computed by dividing net (loss) income by the weighted average number of common shares outstanding during the period. We apply the two-class method in calculating earnings per share. Accretion associated with the redeemable shares of Class A common stock is excluded from earnings per share as the redemption value approximates fair value. As of December 31, 2021 and December 31, 2020, we had outstanding warrants to purchase up to 14,519,228 shares of Class A common stock. The weighted average of these shares was excluded from the calculation of diluted net (loss) income per share of common stock since the exercise of the warrants is contingent upon the occurrence of future events. As of December 31, 2021, we did not have any dilutive securities or other contracts that could, potentially, be exercised or converted into shares of common stock and then share in our earnings. As a result, diluted net (loss) income per common share is the same as basic net (loss) income per common share for the periods presented. Reconciliation of Net Earnings (Loss) per common share Basic and diluted loss per common share is calculated as follows: ​ ​ For the Year Ended December 31, 2021 ​ ​ For the Period from August 25, 2020 (inception) through December 31, 2020 ​ ​ Class A ​ ​ Class B ​ ​ Class A ​ ​ Class B Basic and diluted net income (loss) per share ​ ​ ​ ​ ​ ​ ​ ​ Numerator: ​ ​ ​ ​ ​ ​ ​ ​ Allocation of net income (loss) ​ ​ $ 2,357,536 ​ ​ $ 589,383 ​ ​ $(1,868,311) ​ ​ $(1,156,493) ​ ​ ​ ​ ​ ​ ​ ​ Denominator: ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average shares outstanding ​ ​ 13,598,898 ​ ​ 3,399,724 ​ ​ 6,975,341 ​ ​ 4,317,769 ​ ​ ​ ​ ​ ​ ​ ​ Basic and diluted net income (loss) per share ​ ​ $ 0.17 ​ ​ $ 0.17 ​ ​ $ (0.27) ​ ​ $ (0.27)
Cash and Cash Equivalents, Policy [Policy Text Block]	Cash and Cash Equivalents The Company considers all highly liquid instruments purchased with an original maturity of three
Concentration Risk, Credit Risk, Policy [Policy Text Block]	Concentration of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist of cash accounts in a financial institution, which, at times, may exceed the Federal Depository Insurance Coverage of $250,000. At December 31, 2021, the Company has not experienced losses on these accounts and management believes the Company is not exposed to significant risks on such accounts.
Fair Value Measurement, Policy [Policy Text Block]	Financial Instruments The fair value of the Company’s assets and liabilities, which qualify as financial instruments under Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 820, “Fair Value Measurements and Disclosures,” approximates the carrying amounts presented in the balance sheet.
Use of Estimates, Policy [Policy Text Block]	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires the Company’s 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 could differ from those estimates.
Derivatives, Policy [Policy Text Block]	Warrants Liability We account for the warrants in accordance with the guidance contained in Accounting Standards Codification 815 (“ASC 815”), “Derivatives and Hedging”, under which the warrants do not meet the criteria for equity treatment and must be recorded as derivative liabilities. Accordingly, we classify the warrants as liabilities at their fair value and adjust the warrants to fair value at each reporting period. This liability is subject to re-measurement at each balance sheet date until the warrants are exercised, and any change in fair value is recognized in our statement of operations. The fair value of the Private Placement Warrants and the Public Warrants issued in connection with the Public Offering have been measured based on the listed market price of such Warrants.
Income Tax, Policy [Policy Text Block]	Income Taxes The Company follows the asset and liability method of accounting for income taxes under ASC 740, “Income Taxes.” Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statements carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. Valuation allowances are established, when necessary, to reduce deferred tax assets to the amount expected to be realized. For those liabilities or benefits to be recognized, a tax position must be more-likely-than-not to be sustained upon examination by taxing authorities. The Company recognizes accrued interest and penalties related to uncertain tax positions as income tax expense. At December 31, 2021, management has not identified any uncertain tax positions that are not more likely than not to be sustained. The Company may be subject to potential examination by U.S. federal, states or foreign jurisdiction authorities in the areas of income taxes. These potential examinations may include questioning the timing and amount of deductions, the nexus of income amounts in various tax jurisdictions and compliance with U.S. federal, states or foreign tax laws. The Company is incorporated in the State of Delaware and is required to pay franchise taxes to the State of Delaware on an annual basis.
Temporary Equity [Policy Text Block]	Redeemable Shares of Class A Common Stock All of the 13,598,898 shares of Class A common stock sold as parts of the Units in the Public Offering contain a redemption feature. In accordance with the Accounting Standards Codification 480-10-S99-3A (“ASC 480”), “Classification and Measurement of Redeemable Securities”, redemption provisions not solely within the control of the Company require the security to be classified outside of permanent equity. Ordinary liquidation events, which involve the redemption and liquidation of all of the entity’s equity instruments, are excluded from the provisions of ASC 480. The Company classifies all shares of Class A common stock as redeemable.
New Accounting Pronouncements, Policy [Policy Text Block]	Recently issued accounting pronouncements not yet adopted Management does not not

Note 2 - Significant Accounti_2

Note 2 - Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2021
us-gaap_TableTextBlock
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	​ ​ For the Year Ended December 31, 2021 ​ ​ For the Period from August 25, 2020 (inception) through December 31, 2020 ​ ​ Class A ​ ​ Class B ​ ​ Class A ​ ​ Class B Basic and diluted net income (loss) per share ​ ​ ​ ​ ​ ​ ​ ​ Numerator: ​ ​ ​ ​ ​ ​ ​ ​ Allocation of net income (loss) ​ ​ $ 2,357,536 ​ ​ $ 589,383 ​ ​ $(1,868,311) ​ ​ $(1,156,493) ​ ​ ​ ​ ​ ​ ​ ​ Denominator: ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average shares outstanding ​ ​ 13,598,898 ​ ​ 3,399,724 ​ ​ 6,975,341 ​ ​ 4,317,769 ​ ​ ​ ​ ​ ​ ​ ​ Basic and diluted net income (loss) per share ​ ​ $ 0.17 ​ ​ $ 0.17 ​ ​ $ (0.27) ​ ​ $ (0.27)

Note 5 - Income Taxes (Tables)

Note 5 - Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
us-gaap_TableTextBlock
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	​ ​ Year ended December 31, ​ ​ 2021 ​ ​ 2020 Income tax expense (benefit): ​ ​ ​ ​ Deferred federal income tax expense (benefit) ​ ​ (767,176) ​ ​ (93,745) Deferred state income tax expense (benefit) ​ ​ (225,399) ​ ​ (32,634) ​ ​ ​ ​ Total Income Tax Benefit Before Valuation Allowance ​ ​ (992,575) ​ ​ (126,379) ​ ​ ​ ​ Valuation allowance ​ ​ 992,575 ​ ​ 126,379 ​ ​ ​ ​ Total Income Tax Expense (Benefit) ​ ​ $ — ​ ​ $ —
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	​ ​ For the Year Ended December 31, 2021 ​ ​ For the Period from August 25, 2020 (inception) through December 31, 2020 Income tax expense (benefit) at the federal statutory rate ​ ​ $ 618,853 ​ ​ $ (93,745) State income taxes (benefit) - net of federal income tax benefits ​ ​ 182,709 ​ ​ (32,634) Unrealized gain on warrants ​ ​ (1,657,887) ​ ​ — Unrealized gain on securities ​ ​ (440) ​ ​ — Other, net ​ ​ (9,431) ​ ​ — Change in valuation allowance ​ ​ 866,196 ​ ​ 126,379 Total income tax expense (benefit) ​ ​ $ — ​ ​ $ —
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	Net operating loss carryforwards ​ ​ $ 455,199 ​ ​ $ 126,379 Start-up costs ​ ​ 537,376 ​ ​ — Valuation allowance ​ ​ (992,575) ​ ​ (126,379) Total deferred tax asset ​ ​ $ — ​ ​ $ —

Note 1 - Organization and Bus_2

Note 1 - Organization and Business Operations (Details) - USD ($)	Jan. 25, 2022	Dec. 22, 2021	Aug. 25, 2021	Dec. 31, 2021	Dec. 01, 2020	Oct. 26, 2020
Equity Issued During Period, Price Per Unit (in dollars per share)						$ 10.20
Business Combination, Required Fair Market Value, Percentage of Net Assets Held in Trust Account				80.00%
Business Combination, Minimum Percentage of Voting Interest Acquired				50.00%
Subsequent Event [Member]
Shares Issued, Price Per Share (in dollars per share)	$ 10
Stock Redeemed or Called During Period, Shares (in shares)	12,061,041
Proceeds from IPO [Member]
Assets Held-in-trust, Total						$ 127,500,000
Proceeds from Over-allotment Option [Member]
Assets Held-in-trust, Total					$ 10,988,980
Boston Omaha [Member]
Purchase Agreement, Provided Financing		$ 45,000,000
Shares Issued, Price Per Share (in dollars per share)		$ 10
Purchase Agreement, Minimum Financing Amount Waived		$ 150,000,000
Senior Bonds [Member] | Sky Harbour Capital LLC [Member] | Public Finance Authority [Member]
Proceeds from Issuance of Secured Tax Exempt Debt			$ 166,000,000
Bond, Weighted Average Amortization Period (Year)			24 years
Senior Bonds Maturing In 2036 [Member] | Sky Harbour Capital LLC [Member] | Public Finance Authority [Member]
Debt Instrument, Interest Rate, Stated Percentage			3.80%
Senior Bonds Maturing In 2041 [Member] | Sky Harbour Capital LLC [Member] | Public Finance Authority [Member]
Debt Instrument, Interest Rate, Stated Percentage			4.00%
Senior Bonds Maturing In 2054 [Member] | Sky Harbour Capital LLC [Member] | Public Finance Authority [Member]
Debt Instrument, Interest Rate, Stated Percentage			4.25%

Note 2 - Significant Accounti_3

Note 2 - Significant Accounting Policies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Weighted Average Number Diluted Shares Outstanding Adjustment, Total (in shares)	0
Unrecognized Tax Benefits, Ending Balance	$ 0
Common Class A [Member]
Temporary Equity, Shares Outstanding (in shares)	13,598,898	13,598,898
Warrants Issued in Connection with Units [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	14,519,228	14,519,228

Note 2 - Summary of Significant

Note 2 - Summary of Significant Accounting Policies - Reconciliation of Net Loss Per Common Share (Details) - USD ($)	4 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2021
Common Class A [Member]
Allocation of net income (loss)	$ (1,868,311)	$ 2,357,536
Weighted-average shares outstanding (in shares)	6,975,341	13,598,898
Class A common stock - basic and diluted (in dollars per share)	$ (0.27)	$ 0.17
Common Class B [Member]
Allocation of net income (loss)	$ (1,156,493)	$ 589,383
Weighted-average shares outstanding (in shares)	4,317,769	3,399,724
Class A common stock - basic and diluted (in dollars per share)	$ (0.27)	$ 0.17

Note 3 - Initial Public Offer_2

Note 3 - Initial Public Offering (Details) - USD ($)	Dec. 01, 2020	Oct. 26, 2020
Warrants Issued in Connection with Units [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)		1
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)		$ 11.50
IPO [Member]
Units Issued During Period, Number (in shares)		12,500,000
Units Issued During Period, Price Per Unit (in dollars per share)		$ 10
Proceeds from Issuance or Sale of Equity, Total		$ 125,000,000
Units Issued During Period, Number of Warrants (in shares)		0.5
IPO [Member] | Common Class A [Member]
Units Issued During Period, Number of Common Stock Shares (in shares)		1
Over-Allotment Option [Member] | Underwriters [Member]
Units Issued During Period, Number (in shares)	1,098,898
Units Issued During Period, Price Per Unit (in dollars per share)	$ 10
Over-allotment Option, Term (Day)	45 days
Over-Allotment Option [Member] | Underwriters [Member] | Maximum [Member]
Over-allotment Option, Number of Units Called by Options (in shares)	1,875,000

Note 4 - Related Party Transa_2

Note 4 - Related Party Transactions (Details)	Dec. 01, 2020$ / sharesshares	Oct. 26, 2020USD ($)$ / sharesshares	Aug. 31, 2020USD ($)$ / sharesshares	Dec. 31, 2020$ / sharesshares	Dec. 31, 2020USD ($)$ / sharesshares	Dec. 31, 2021USD ($)$ / sharesshares	Sep. 27, 2021USD ($)
Stock Issued During Period, Value, New Issues | $					$ 25,000
Proceeds from Issuance of Warrants | $					$ 7,719,779	$ 0
Promissory Note [Member] | BOC Yellowstone LLC [Member]
Line of Credit Facility, Maximum Borrowing Capacity | $							$ 1,000,000
Long-term Debt, Total | $						$ 1,000,000
Proceeds from Private Placement Warrants [Member]
Assets Held-in-trust, Total | $		$ 5,000,000
Private Placement Warrant [Member]
Class of Warrant or Right, Issued During Period (in shares) | shares	219,779	7,500,000
Class of Warrant or Right, Issued During Period, Purchase Price (in dollars per share) | $ / shares	$ 1	$ 1
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) | shares		1
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares		$ 11.50
Proceeds from Issuance of Warrants | $		$ 7,500,000
Conversion Warrant [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) | shares						1
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares						$ 1.50
BOC Yellowstone LLC [Member]
Related Party, Working Capital Loan, Conversion, Price Per Warrant (in dollars per share) | $ / shares						1.50
Common Class B [Member]
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares				$ 0.0001	$ 0.0001	$ 0.0001
Common Stock, Shares, Outstanding, Ending Balance (in shares) | shares				3,399,724	3,399,724	3,399,724
Common Class B [Member] | BOC Yellowstone LLC [Member]
Stock Issued During Period, Shares, New Issues (in shares) | shares			5,750,000
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares			$ 0.0001
Stock Issued During Period, Value, New Issues | $			$ 25,000
Common Stock, Shares Surrendered (in shares) | shares				2,350,276
Common Stock, Shares, Outstanding, Ending Balance (in shares) | shares				3,399,724	3,399,724	3,399,724
Common Stock, Conversion Rate						1

Note 5 - Income Taxes (Details)

Note 5 - Income Taxes (Details) $ in Millions	Dec. 31, 2021USD ($)
Domestic Tax Authority [Member]
Operating Loss Carryforwards, Total	$ 1.7
State and Local Jurisdiction [Member]
Operating Loss Carryforwards, Total	$ 1.7

Note 5 - Income Taxes - Income

Note 5 - Income Taxes - Income Tax Expense (Benefit) (Details) - USD ($)	4 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Deferred federal income tax expense (benefit)		$ (767,176)	$ (93,745)
Deferred state income tax expense (benefit)		(225,399)	(32,634)
Total Income Tax Benefit Before Valuation Allowance		(992,575)	(126,379)
Valuation allowance		992,575	126,379
Total income tax expense (benefit)	$ 0	$ 0	$ 0

Note 5 - Income Taxes - Effecti

Note 5 - Income Taxes - Effective Income Tax Rate Reconciliation (Details) - USD ($)	4 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Income tax expense (benefit) at the federal statutory rate		$ (618,853)	$ 93,745
State income taxes (benefit) - net of federal income tax benefits		(182,709)	32,634
Unrealized gain on warrants		(1,657,887)	0
Unrealized gain on securities		(440)	0
Other, net		(9,431)	0
Change in valuation allowance		(866,196)	(126,379)
Total income tax expense (benefit)	$ 0	$ 0	$ 0

Note 5 - Income Taxes - Compone

Note 5 - Income Taxes - Components of Deferred Tax Asset (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Net operating loss carryforwards	$ 455,199	$ 126,379
Start-up costs	537,376	0
Valuation allowance	(992,575)	(126,379)
Total deferred tax asset	$ 0	$ 0

Note 6 - Stockholders' Equity (

Note 6 - Stockholders' Equity (Details)	Nov. 16, 2020USD ($)shares	Dec. 31, 2021$ / sharesshares	Dec. 31, 2020$ / sharesshares	Aug. 31, 2020$ / shares
Common Stock, Voting Rights Per Share		1
Preferred Stock, Shares Authorized (in shares)		1,000,000	1,000,000
Preferred Stock, Shares Issued, Total (in shares)		0	0
Preferred Stock, Shares Outstanding, Ending Balance (in shares)		0	0
BOC Yellowstone LLC [Member] | BOC Yellowstone II LLC [Member]
Proceeds from Divestiture of Interest in Subsidiaries and Affiliates, Total | $	$ 309,375
Investment Owned, Shares to Be Transferred Upon Initial Business Combination (in shares)	206,250
BOC Yellowstone LLC [Member] | Class B Common Stock of Yellowstone Acquisition Company [Member] | BOC Yellowstone II LLC [Member]
Investment Owned, Shares Transferred (in shares)	206,250
Common Class A [Member]
Common Stock, Shares Authorized (in shares)		200,000,000	200,000,000
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares		$ 0.0001	$ 0.0001
Common Stock and Temporary Equity, Shares, Issued (in shares)		13,598,898
Common Stock and Temporary Equity, Shares, Outstanding (in shares)		13,598,898
Common Class B [Member]
Common Stock, Shares Authorized (in shares)		20,000,000	20,000,000
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares		$ 0.0001	$ 0.0001
Common Stock, Shares, Outstanding, Ending Balance (in shares)		3,399,724	3,399,724
Common Stock, Conversion Features, Period After Completion of Initial Business Combination (Year)		1 year
Common Stock, Conversion Features, Minimum Sale Price For 20 Days, Class A Common Stock, At Least 150 Days After Initial Business Combination (in dollars per share) | $ / shares		$ 12
Common Class B [Member] | BOC Yellowstone LLC [Member]
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares				$ 0.0001
Common Stock, Shares, Outstanding, Ending Balance (in shares)		3,399,724	3,399,724
Common Stock, Conversion Rate		1

Note 7 - Commitments (Details)

Note 7 - Commitments (Details)	Dec. 31, 2021USD ($)$ / shares
Underwriting Agreement, Cash Underwriting Discount, Per Unit (in dollars per share) | $ / shares	$ 0.20
Underwriting Agreement, Cash Underwriting Discount, Aggregate Amount | $	$ 2,500,000
Underwriting Agreement, Deferred Fee, Per Unit (in dollars per share) | $ / shares	$ 0.35
Underwriting Agreement, Cash Underwriting Discount, Aggregate Amount Including Underwriter Shares | $	$ 4,759,615

Note 8 - Fair Value Measureme_2

Note 8 - Fair Value Measurements (Details) - USD ($)	4 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2021
Fair Value Adjustment of Warrants	$ 2,070,328	$ (6,095,170)
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Derivative Liability, Total		11,908,671
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Investments, Fair Value Disclosure, Total		69,382,121
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | US Treasury Securities [Member]
Investments, Fair Value Disclosure, Total		$ 69,378,000

Note 9 - Subsequent Events (Det

Note 9 - Subsequent Events (Details) - USD ($)	Mar. 02, 2022	Jan. 25, 2022	Dec. 31, 2020	Dec. 31, 2021
Payments of Stock Issuance Costs			$ 3,201,504	$ 0
Common Class A [Member]
Proceeds from Issuance of Common Stock			$ 135,988,980	$ 0
Subsequent Event [Member]
Shares Issued, Price Per Share (in dollars per share)		$ 10
Proceeds from Issuance of Common Stock		$ 45,000,000
Payments of Stock Issuance Costs		$ 4,759,615
Subscription Agreement, Offering Fee, Percent		3.50%
Repayments of Notes Payable		$ 1,000,000
Subsequent Event [Member] | AA's Underlying Ground Lease [Member]
Lessee, Operating Lease, Amount Purchased	$ 8,500,000
Lessee, Operating Lease, Purchased, Transfer Fee	$ 1,000,000
Lessee, Operating Lease, Term of Contract (Year)	10 years
Subsequent Event [Member] | Common Class A [Member]
Stock Issued During Period, Shares, New Issues (in shares)		4,500,000