Someone has finally answered the question we all didn’t know we wanted to ask.

NEW YORK - MID 1950's: Passengers enjoy a relaxing smoke on a Transocean Air lines Boeing 377 Stratocruiser in the mid 1950's. Transocean Air lines flew between 1946 and 1962 and was a pioneer discount airline. (Photo by Michael Ochs Archive/Getty Images
Credit: Getty Images

It's been 28 years since the federal government banned smoking on US domestic flights (most international airplanes following suit shortly thereafter). And yet, take a look around on your next plane ride: there's an ashtray in the lavatory. And according to a recently resurfaced Business Insider article, those ashtrays aren’t just vestiges on outdated airplanes.

Ashtrays are actually part of the Federal Aviation Administration's minimum equipment list—in order to fly, an airplane must have an ashtray.

Airlines are afraid that, despite the countless “no smoking” signs and announcements, some badly behaved passenger will light up anyway—and toss the cigarette into the paper-filled waste basket.

Turns out, the FAA isn’t just being a big worrywart. In 1973, Varig Flight 820 from Rio de Janeiro to Paris ended in tragedy when a major fire started near the bathroom, a blaze supposedly stemming from a lit cigarette tossed into the lavatory trash. Almost everyone onboard died of smoke inhalation before the plane could make an emergency landing.

To this we say, please do not ignore the illuminated signs, captain's announcements, and illustrated warnings. There are more than a handful of good reasons not to smoke on an airplane (and yes, electronic cigarettes count, too). But if you must break the law, please dispose of the evidence in the bathroom ashtray.

Melanie Lieberman is the Assistant Digital Editor at Travel + Leisure. Follow her on Twitter and Instagram at @melanietaryn.