Note 1 - Summary of Significant Accounting Policies (Details Textual)	3 Months Ended								12 Months Ended
	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Apr. 01, 2019 USD ($)
Revenues, Total	$ 76,003,000	$ 63,623,000	$ 49,341,000	$ 60,867,000	$ 53,460,000	$ 44,501,000	$ 48,861,000	$ 47,697,000	$ 249,834,478	$ 194,519,345
Warranty Term on Ground Equipment Products									3 years
Number of Reportable Segments									6
Subsequent Event [Member] | Accounting Standards Update 2016-02 [Member]
Operating Lease, Right-of-Use Asset											$ 10,700,000
Operating Lease, Liability, Total											$ 11,200,000
Overnight Air Cargo [Member]
Revenues, Total									$ 72,978,361	72,845,353
Overnight Air Cargo [Member] | Cargo and Freight [Member]
Revenues, Total									$ 23,578,000	$ 23,380,000
Computer Equipment [Member]
Property, Plant and Equipment, Useful Life									3 years
Flight Equipment [Member]
Property, Plant and Equipment, Useful Life									7 years
Equipment Leased to Other Party [Member]
Property, Plant and Equipment, Useful Life									10 years
Building [Member]
Property, Plant and Equipment, Useful Life									30 years