A 'Combi' was soon offered to allow simultaneous carriage of passengers and cargo on the main deck. A freighter model, with a large nose cargo door, allows outsized payloads to be carried. Continued development in the ensuing years has increased payload, range, and capability with multiple 747 variants. The 747 quickly became a mainstay of the world’s international airlines. The first 747 engine, the Pratt & Whitney JT9D, was an equally challenging engineering effort it experienced numerous problems in initial service. First flight occurred on February 9, 1969, followed by an extensive test program. The leviathan 747 required an all-new factory, which was built almost simultaneously with the first 747 at Paine Field in Everett, Washington. It triggered a revolution in air travel and represents a significant milestone in the evolution of aviation design.
With its massive size and signature upper deck 'hump,' the iconic 747 is one the most recognizable aircraft in the world. But the gamble paid off – over 1,500 units have been produced. Developing what was then the world's largest passenger aircraft was a formidable undertaking, requiring the company to risk much of its net worth. The growing worldwide demand for air travel during the 1960s led Boeing to launch the 747, the first wide-body jet.
