Note 2 - Acquisitions - Assets Acquired and Liabilities Assumed by AirCo (Details) - USD ($)		9 Months Ended
	May 02, 2017	Dec. 31, 2017	Dec. 31, 2016
Consideration paid		$ 2,900,000	$ 4,573,700
AirCo [Member] | Acquired Inventory and Principal Business Assets, and Assumed Specified Liabilities, of Aircraft Instrument and Radio Company, Incorporated, and Aircraft Instrument and Radio Services, Inc. [Member]
Accounts receivable	$ 748,936
Inventories	3,100,000
Property and equipment	26,748
Accounts payable	(313,117)
Accrued expenses	(382,687)
Net Assets	3,179,880
Consideration paid	2,400,000
Business Combination, Bargain Purchase, Gain Recognized, Amount	$ 779,880