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Aero Spacelines, Inc. was an American aircraft manufacturer from 1960 to 1968 which made a name for itself by converting Boeing 377 Stratocruisers into the famous Guppy line of airplanes, re-engineered solely for transporting oversized cargo such as space exploration vehicles.
Aero Spacelines was formed with only one customer in mind. NASA required a way to transport outsized cargo from their suppliers' manufacturing plants to Cape Canaveral Air Force Station in Florida. Their freight shipments were too large to be safely transported by rail or truck; shipping by sea was time consuming, expensive, and fraught with the danger of damaging the shipments on turbulent seas. The only viable means of transporting NASA's cargo was by air. However, due to the large size of the components, no existing aircraft was capable of accomplishing the task.
John M. "Jack" Conroy, an ex-United States Air Force pilot, and Lee Mansdorf, an aircraft salesman and entrepreneur, formulated the Guppy concept one evening over dinner. It was decided a company needed to be established to manufacture outsized aircraft. Conroy hired Robert W. Lillibridge as Vice President-Manufacturing and Engineering, and assembled a team for the project. Financing was provided by venture capitalist William Ballon, a World War II combat veteran from the Army Air Corps. Once the company was established at Van Nuys Airport, California, Aero Spacelines began in 1960 to engineer the transformation of the Boeing 377 airliner into the Pregnant Guppy.
Among the earliest of NASA's shipments utilizing the Pregnant Guppy were the first and second stages of the Gemini Program's Titan II GVL from the Martin Co. in Baltimore, Maryland, to Cape Canaveral, Florida. Subsequent versions of the Guppy series transported the S-IVB, the third stage of the Saturn booster from California to Florida.
In 1967, Aero Spacelines encountered financial difficulties and was acquired by Unexcelled Inc. That corporation was sold to Tracor Aviation. Jack Conroy organized a new company, Conroy Aircraft, which built more airplanes for transporting oversized cargo. By November 1968, NASA had paid Aero Spacelines $11,591,633 in contracts. Conroy ceased operations in 1972.
As of July 2012, one Super Guppy is still in operation. NASA uses it to transport its vehicles as needed, and leases it to third parties in the meantime.
In early 2016, NASA used this aircraft to transport the main structure of Orion Mars exploration crew capsule, from its assembly facility in Michoud, Louisiana, to Kennedy Space Center in Florida, where the capsule will undergo its first unmanned test flight aboard the Space Launch System rocket. 
List of aircraft
Aero Spacelines produced three Guppy aircraft models while it was in business.
- Mondey, p. 9
- "NASA website, updated 12 July 2012: 377SG-201 is still in use". Archived from the original on 2013-02-15. Retrieved 2013-02-11.
- Pregnant Guppy : THE PLANE THAT WON THE SPACE RACE Bloom, Margy. May / June 2010, PILOTMAG Magazine
- It's a Plane: One man's obsession, it helped get us to the moon Tripp, Robert S. Spring 2002, American Heritage of Invention and Technology
- Page about Airbus Industrie's Beluga
- Site about The Guppy Family of Aircraft
- The Day the Super Guppy Blew Her Top