Setting the scene
Airlines wanted a short-haul jet smaller than the 707 to serve regional routes profitably, and Boeing bet that a narrow-body design could dominate airports worldwide.
What happened
The Boeing 737 first flew on April 9, 1967, from Boeing Field in Seattle; the -100 series seated about 100 passengers and shared design DNA with the larger 727.
Why it still matters
The 737 family became the best-selling commercial jetliner in history, powering budget carriers from Southwest to Ryanair. Memorable detail: early 737s had engines mounted directly under the wings, giving the plane a distinctive "hamster pouch" profile.
Background
The narrow-body design later dominated budget airlines worldwide.