Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Jul. 31, 2024	Apr. 30, 2024
Supplemental type certificates, accumulated amortization	$ 12,110	$ 11,810
Other assets, accumulated amortization	$ 13,263	$ 13,041
Preferred stock, par value (in dollars per share)	$ 5	$ 5
Preferred stock, shares authorized (in shares)	50,000,000	50,000,000
Preferred stock, designated classes (in shares)	200,000	200,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	100,000,000	100,000,000
Common stock, issued (in shares)	79,646,211	79,646,211
Common stock, outstanding (in shares)	68,270,856	68,770,856
Treasury stock, shares (in shares)	11,375,355	10,875,355