Window seats with a substantial view of the wing are a thrill to some and a scourge to others – why are those flaps moving? Is the wing meant to shake that much? Is that a gremlin?

But window seats don’t exist entirely for the passenger’s benefit – they’re also required by the pilot.

If the crew believe there is an issue with a wing – the flaps, the slats or even engines – looking out of the window is the best way to verify visually their concerns, one way or another.

And to do that they will head to the best seat in the house, usually marked by a small black triangle on the interior cabin wall.

“The black triangle marks the location of what has been called William Shatner’s Seat, the seat with the clearest view of the wing,” explained retired aerospace engineer Lee Ballentine after the question was posed on Q&A website Quora.

“This is the place inside the airplane from which you can get the best visual check for ice or other problems. The Shatner reference is to one of the strangest Twilight Zone episodes, Nightmare at 20,000 Feet, which first aired on October 11, 1963. In it, Shatner’s character sees a gremlin on the wing of the plane he’s a passenger on.”

Another respondent said that advances in technology means that visual checks from William Shatner’s Seat occur less and less.

“So why are they still there? Because airplanes are expensive, so last forever,” said airline pilot Steven Hoober. “Features are never removed, and useless ones are generally still maintained.”

Another response, from Donald Daugherty, an aerospace engineer, said that the position on some Airbus planes is used to spot, if in doubt, that the landing gear is down, seen via a post that protrudes from the wing at a particular position.

“[The crew] usually asks a flight attendant to look out as to not frighten anyone,” he said.

The spot also provides, for those interested, the best position for those glorious wing-shot Instagram pics.

Another element of the wing to cause consternation in some passengers is the handles or hooks on the wing, pictured below, often yellow and easily visible from a number of window seats.

The yellow hooks on plane wings are used for emergency slide ropes Credit: Getty

These are used to help secure the rope connecting the life raft in the case of an emergency landing on water, as well as providing something to guide passengers walking across the wing when leaving the aircraft.

One of our favourite befuddling additions to aircraft, however, is the ashtray in a plane bathroom – despite no-one being allowed to smoke on a plane this side of the millennium.

So why still have them? Read on for the answer.

Inspiration for your inbox

Sign up to Telegraph Travel's new weekly newsletter for the latest features, advice, competitions, exclusive deals and comment.

You can also follow us on Twitter, Facebook and Instagram.