What's behind better-behaving air passengers?

Score one for social media and zero for badly behaved airline passengers.

Cases of "unruly passengers" plunged to only 85 last year, according to the Federal Aviation Administration. That's the lowest number since 1995, and it represents only about one-quarter of such incidents that occurred in 2004, when the FAA tracked a record 310 disruptive passengers.

The reason may be due to the ubiquity of smartphones and social media, given that bad behavior is increasingly likely to be caught on video and blasted across Twitter (TWTR), Facebook (FB) and other social media forums.

Take the case of the passenger on a flight from Iceland to New York who allegedly attacked another passenger and screamed that the flight was going to crash. He ended up duct-taped to his seat, and his heavily taped mug was plastered across social media.

That may be dissuading some would-be unruly types for letting loose their bad sides while in midair, said George Hobica, founder of Airfarewatchdog.

"Everyone has a camera now, and they'll nail you to the social media cross," Hobica said. "It's like being put in the stocks."

While other passengers are ready to take a snapshot or hit "record," airline crews are increasingly vigilant, he added. "Abusive behavior, bad language, refusal to follow crew member instructions" are all issues that can get passengers in trouble, he said.

"Because (crews) are more intolerant, people know they can't get away with it," Hobica said. It has "put the fear of god into the passengers."

Aside from getting kicked off the plane, unruly passengers can also end banned by the airline.

They're also expensive -- both for the airline and the badly behaved passengers themselves. Unscheduled landings to take care of a disruptive passenger can cost as much as $200,000 for the airlines, while the perpetrator can face a fine of up to $25,000.