The tradition of Boeing airplanes having names that start and end with the number 7 began in the 1950s when the company decided to categorize its products by numerical series.

This 1956 model was an early concept for the Boeing 727, which quickly became an airline standard but ended up looking nothing like this design. The 727 was ultimately built with two engines on ...

Developed as a successor to the Boeing 727, it may not have been the best-selling single-aisle model in Boeing's history, but it continues to serve in commercial and cargo operations today.