The first flight of the Lockheed C-5 Galaxy was on June 30, 1968. Since then this enormous aircraft has aided the United States Air Force by transporting bulky combat equipment and other cargo. Its immense payload capabilities make the C-5 Galaxy an impressive asset. Performance concerns, however, have resulted in numerous improved models of the orginial C-5, the most recent being the C-5M. The C-5 Galaxy continues to undergo modifications through the C-5 Avionics Modernization Program.