Boeing 707 version was numbered 707-320. Pan Am was the first airline to operate the 707; the carrier inaugurated 707 service with a christening at National Airport on October 17, 1958, attended by President Eisenhower, followed by a transatlantic flight for VIPs (personal guests of founder Juan Trippe) from Baltimore's Friendship International Airport to Paris. The aircraft's first commercial flight was from Idlewild Airport, New York, to Le Bourget, Paris, on October 26, 1958, with a fuel stop in Gander, Newfoundland. In December, National Airlines operated the first U.S. domestic jet airline flights between New York/Idlewild and Miami, using 707s leased from
Boeing 707 the McDonnell Douglas MD-95 to Boeing 717 after the company was merged with Boeing. Boeing's customer codes used to identify specific options and livery specified by customers was started with the 707, and has been maintained through all Boeing's models. In essence the same system as used on the earlier Boeing 377, the code consisted of two digits affixed to the model number to identify the specific aircraft version. For example, Pan American World Airways was assigned code "21". Thus, a 707-320B sold to Pan Am had the model number 707-321B. The number remained constant as further aircraft were purchased;