The Aero Spacelines Pregnant Guppy was a large, wide-bodied cargo aircraft built in the United States and used for ferrying outsized cargo items, most notably NASA's components of the Apollo moon program. The Pregnant Guppy was the first of the Guppy line of aircraft produced by Aero Spacelines. The design also inspired similar designs such as the jet-powered Airbus Beluga, and the Boeing 747 LCF designed to deliver Boeing 787 parts. In 1960, U.S. airlines were disposing of their obsolete piston-engined Boeing 377 Stratocruisers in favor of the newer jet-engined airliners. NASA was finding that barge transport of their increasingly large space program components from manufacturers on the West Coast to test and launch sites on the East Coast was slow and expensive. Aircraft broker Leo Mansdorf was stockpiling surplus Stratocruisers at Van Nuys prior to resale, and ex-USAF pilot John M. Conroy realized the potential of these aircraft to transport the large but relatively light rocket components. Carrying the S-IV Saturn I rocket stage, the Guppy saved three weeks transit time versus barge, for a cost of $16.00 per mile.