Condensed Consolidated Balance Sheets (Unaudited) - USD ($)	Feb. 28, 2023	May 31, 2022
Current assets
Cash and cash equivalents	$ 3,383,847	$ 22,517,038
Short-term investments	19,276,643	1,097,450
Accounts and other receivables, net	8,563,365	4,466,686
Inventory	5,680,215	5,854,935
Costs and estimated earnings in excess of billings	3,773,987	3,336,474
Other current assets	817,814	704,436
Total current assets	41,495,871	37,977,019
Maintenance and other inventory, net	867,889	1,107,309
Property and equipment, net	11,233,349	9,854,759
Other assets	208,983	205,359
Deferred income taxes	74,615	74,615
Assets	53,880,707	49,219,061
Current liabilities
Accounts payable	1,467,153	1,426,830
Billings in excess of costs and estimated earnings	1,437,996	1,122,763
Other current liabilities	3,279,709	3,414,314
Total current liabilities	6,184,858	5,963,907
Stockholders' Equity
Common stock and additional paid-in capital	10,603,892	10,329,258
Retained earnings	40,061,664	35,840,898
Treasury stock - at cost	(2,969,707)	(2,915,002)
Total stockholders' equity	47,695,849	43,255,154
Liabilities and Equity	$ 53,880,707	$ 49,219,061