Pilot reveals secret why plane windows are rounded — and it’s for a tragic reason

When it comes to airplane windows, it’s not hip to be square.

The shape of airplane windows might seem arbitrary, but there’s actually a grim reason behind their design, according to air experts.

They made them round to keep us safe and sound.

In a TikTok video with over 2 million views, American Airlines pilot Captain Steve explained that portals with rounded edges were installed in the 1950s following a series of inflight catastrophes caused by their rectangular counterparts.

“Some of the airliners were designed with square windows and over in Europe as airplanes started to climb higher and require more pressurization, they discovered a problem,” the flyboy explained.

He added that “they lost a few airplanes in midair” because the windows’ square shape created “a hairline crack” around the edge due to the stress on the airframe.

When enough of these cracks formed, the captain explained, the aircraft literally “came apart” due to decompression.

To prevent these inflight freak accidents, engineers rounded the windows’ frames so they wouldn’t break under the strain — and they’ve “never had a problem since,” according to the pilot.

Viewers were relieved to hear the rationale behind this seemingly inconsequential design choice.

“That makes a lot of sense,” said one commenter, while another wrote, “Thanks for the explanation! The more I know, the easier it is to fly.”

“I’m a terrified flight passenger!” a third admitted. “But, after watching your [TikToks], Captain Steve, I wasn’t so terrified last week on my flights. Thank you!”

Captain Steve didn’t mention the incidents by name, but some viewers surmised he was referring to the UK’s ill-fated de Havilland Comet 1 Aircraft, which experienced a spate of inflight disintegrations between 1953 and 1954, per the Federal Aviation Administration.

After examining the wreckage from several of the crashes, flight forensics experts concluded that the “relatively squarish windows were creating stress concentrations much higher than anticipated.

“These stress concentrations fatigued the material around the window corners, which would quickly lead to a rupture of the fuselage,” the FAA wrote.