The history of the United States Air Force is inextricably bound up in the history of aerospace technology. Major revolutions have influenced the evolution of Air Force capabilities and systems, most notably those of atomic weaponry, the turbojet revolution, supersonic flight, avionics, aerial refueling, spaceflight, precision weaponry, electronic flying controls, composite materials, and stealth. It is worthwhile to take a retrospective look at some of the aerospace challenges and opportunities the Air Force faced and how it took advantage - or failed to take advantage - of them.