He did what?

Passengers on flights do bizarre things all the time — but this one has to be the wildest.

Supposedly, a passenger aboard a Southwest Airlines flight from Baltimore, Maryland, to Denver, Colorado, earlier this week observed another passenger using drugs, as reported by View From The Wing.

Yes, you read that correctly.

Apparently, the drug-using individual took out a “steel box containing numerous bottles.” Initially, it appeared harmless, until the passenger started “using his Dunkin’ Donuts loyalty card to cut lines of cocaine.”

The outlet said the flyer then rolled up a $5 bill to do the deed.

According to a fellow passenger who witnessed the incident, the individual then picked up the cut substance, moved towards the window, and began using it. The witness captured a photo showing the situation. They commented to View From The Wing, “I was shocked! It’s evident from the picture what he was doing. Southwest is starting to resemble Spirit Airlines!”

It’s unknown whether this cocaine-using flyer faced any consequences or if the on-flight crew was made aware of this illegal act.

By law, if a person is caught traveling in an airport with illegal drugs on them, they can potentially have charges pressed against them and be arrested — depending on the circumstances.

The Post reached out to Southwest for comment.

Sadly, this isn’t the first time passengers tried to party a little too hard while onboard a flight.

On an easyJet flight to Ibiza — the party capital of the world — a rowdy bunch of British passengers were accused of “taking pills and drinking alcohol at the same time” while waiting for the flight to take off.

The group was supposedly shouting “Come on Ibizia!” while engaging in unruly behavior.

“Everyone standing, screaming, guys hitting each other, drinking bottles of alcohol one after the other, and stopping the flight attendants from doing their job,” Ibiza resident and fellow passenger on the flight, Erika Barrachina, said.

Barrachina was fearful of the inconsiderate group whom she called “wild animals.”

“I’m not afraid of flying because I’ve flown around the world but I had a panic attack because it was like being in a pub, in a nightclub, but in the air.”

“It was a really wild 2.5-hour flight,” she added.

While easyJet might not have done much, supposedly, Delta took action on one of its recent flights when a flyer was told to spit out​ his tobacco-free nicotine Zyn pouch on a recent flight.

“Got told to spit my Zyn out on a flight. I really didn’t know that was a thing?” ​the person wrote on the Reddit thread r/delta.

“Delta flight, first class (not that that matters). They brought a cup out and asked me to spit my Zyn out,” the​ flier ​said. “They said it was because it was a tobacco product. I didn’t put up a fight and complied right away.