TORONTO — Among travel circles, referring to Boeing aircraft by just their numeric signifiers has become the norm. “I flew a 747” makes total sense among frequent fliers, which is a testament to Boeing’s popularity. But why do their planes always start and end with the number 7?

Newscom.au found the answer to this head-scratching question, which according to Boeing is one of the most common questions they’re asked to this day.

Travellers will be surprised to learn that Boeing’s earlier aircraft didn’t use the number 7; in fact, they had names like Model 40, Model 80 and Model 247. But after World War II, the company was restructured and each department was given a three-digit number.

The company’s engineering department divided the model numbers into blocks of 100 for each of the new product areas. For example, 300s and 400s represented aircraft, 500s were used on turbine engines, 600s for rockets and missiles, and 700s – you guessed it – were used for jet transport aircraft. It was an easy way to keep things organized.

But the marketing department realized that the name Model 700 wasn’t exactly catchy, so instead they suggested the name 707. This started a long-standing pattern, starting with 727, 737 and finally today with the latest Boeing 787 Dreamliner models.

Pretty neat, huh?