If you’re thinking of freaking out on a plane, hope you’re flush with cash, because freak-outs don’t come cheap. Some off-the-rails passengers have been fined and the total is now more than a million bucks.

The FAA just hit a milestone (a bad one) in the total amount of penalties they’ve dished out thus far in 2021 … there have been 3,889 reports of unruly behavior this year, and many of these ridiculous passengers have been socked with huge fines.

Most of the in-flight eruptions involve disputes over mask-wearing. There are also a bunch of alcohol-related disturbances. For example …

— A JetBlue passenger was fined $45,000 for throwing objects, including his carry-on at other passengers, lying on the aisle floor, and then grabbing a flight attendant by the ankles and putting his head up her skirt.

— A Frontier Airlines passenger was socked with a $30,000 fine after trying to gain entry to the cockpit by assaulting 2 flight attendants, threatening to kill one of them, and demanding they open the door.

— A JetBlue passenger was fined $17,530 for failing to comply with the mask mandate, vaping on the plane and drinking alcohol not served by the airline.

— An Allegiant Airlines passenger was fined $10,500 for refusing to wear a face mask and then urinating on the bathroom floor, which leaked into the galley.

Turns out a lot of these passengers got dinged for bringing alcohol on board — which is a no-no — and then getting belligerent.

The fines we were provided are all hefty — starting at $7,500. On top of that, some passengers have been charged with crimes.

It’s gotten so bad, flight attendants are now duct-taping out-of-control passengers to their seats.

The FAA has launched a public awareness campaign to curb the insanity on commercial planes.