Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2024	Jan. 31, 2023	Jan. 31, 2024	Jan. 31, 2023
REVENUE:
Revenues from customers	$ 18,960	$ 20,464	$ 55,746	$ 55,093
COSTS AND EXPENSES:
Marketing and advertising	1,216	1,324	3,854	4,023
General, administrative and other	4,008	4,777	11,290	12,296
Total costs and expenses	15,165	17,079	47,215	46,081
OPERATING INCOME	3,795	3,385	8,531	9,012
OTHER INCOME (EXPENSE):
Interest expense	(615)	(677)	(1,869)	(2,107)
Interest income	83	0	199	0
Total other income (expense)	(532)	(677)	2,499	(2,038)
INCOME BEFORE INCOME TAXES	3,263	2,708	11,030	6,974
Gain on sale of airplanes			4,169	0
Gain on sale of building			0	69
PROVISION FOR INCOME TAXES:
Provision for income taxes	881	731	2,978	1,603
NET INCOME	$ 2,382	$ 1,977	$ 8,052	$ 5,091
BASIC EARNINGS PER COMMON SHARE (in dollars per share)	$ 0.03	$ 0.03	$ 0.11	$ 0.07
WEIGHTED AVERAGE SHARES USED IN PER SHARE CALCULATION (in shares)	69,634,335	76,663,867	70,984,870	76,633,871
DILUTED EARNINGS PER COMMON SHARE (in dollars per share)	$ 0.03	$ 0.03	$ 0.11	$ 0.07
WEIGHTED AVERAGE SHARES USED IN PER SHARE CALCULATION (in shares)	69,634,335	76,663,867	70,984,870	76,633,871
Deferred Income Tax Expense (Benefit)			$ 0	$ 280
Professional Services [Member]
REVENUE:
Revenues from customers	$ 9,941	$ 9,574	28,751	28,280
COSTS AND EXPENSES:
Cost of services and products	4,023	3,789	11,976	11,164
Aerospace Products [Member]
REVENUE:
Revenues from customers	9,019	10,890	26,995	26,813
COSTS AND EXPENSES:
Cost of services and products	$ 5,918	$ 7,189	$ 20,095	$ 18,598