Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Jul. 31, 2022	Apr. 30, 2022
CURRENT ASSETS:
Cash	$ 14,796	$ 12,487
Accounts receivable, net of allowance for doubtful accounts	3,615	3,636
Inventories
Parts and raw materials	4,916	4,722
Work in process	4,333	4,080
Finished goods	72	70
Total inventory, net of allowance	9,321	8,872
Contract asset	1,144	1,470
Prepaid expenses and other current assets	1,602	1,361
Total current assets	30,478	27,826
PROPERTY, PLANT AND EQUIPMENT:
Lease right-to-use assets	3,781	3,240
Construction in progress	0	6,417
Land	4,751	4,751
Building and improvements	47,772	40,962
Aircraft	8,798	8,719
Machinery and equipment	5,027	4,917
Office furniture and fixtures	12,399	11,826
Leasehold improvements	4,032	4,032
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, before Accumulated Depreciation and Amortization	86,560	84,864
Accumulated depreciation	(24,170)	(23,290)
Total property, plant and equipment	62,390	61,574
SUPPLEMENTAL TYPE CERTIFICATES (net of accumulated amortization of $9,681 at July 31, 2022 and $9,336 at April 30, 2022)	8,084	8,018
OTHER ASSETS:
Other assets (net of accumulated amortization of $11,745 at July 31, 2022 and $11,575 at April 30, 2022)	1,524	1,621
Deferred tax asset, net	1,490	1,770
Total other assets	3,014	3,391
Total assets	103,966	100,809
CURRENT LIABILITIES:
Current maturities of long-term debt	5,054	5,165
Current maturities of lease liability	136	106
Accounts payable	2,736	2,773
Contract liability	4,164	820
Gaming facility mandated payment	1,322	1,630
Compensation and compensated absences	1,539	1,911
Income taxes payable	1,309	1,049
Other current liabilities	348	211
Total current liabilities	16,608	13,665
LONG-TERM LIABILITIES
Long-term debt, net of current maturities	42,220	43,411
Lease liability, net of current maturities	3,391	2,899
Total long-term liabilities	45,611	46,310
Total liabilities	62,219	59,975
COMMITMENTS AND CONTINGENCIES
STOCKHOLDERS' EQUITY:
Common stock, par value $.01: authorized 100,000,000 shares issued 80,673,572 shares, and outstanding 76,781,507 shares at July 31, 2022 and issued 80,348,572 shares, and outstanding 76,458,146 shares at April 30, 2022	807	803
Capital contributed in excess of par	12,640	12,160
Treasury stock at cost, 3,892,065 shares at July 31, 2022 and 3,890,426 shares at April 30, 2022	(2,079)	(2,077)
Retained earnings	30,379	29,948
Total stockholders' equity	41,747	40,834
Total liabilities and stockholders' equity	103,966	100,809
Preferred Class A [Member]
STOCKHOLDERS' EQUITY:
Preferred stock	0	0
Preferred Class B [Member]
STOCKHOLDERS' EQUITY:
Preferred stock	$ 0	$ 0