Celebrity airport arrests were once big, splashy affairs – Paul McCartney getting arrested in Japan for marijuana possession, or a frenzied Courtney Love flinging her underwear around Heathrow.

Now, the frustrations of air travel in the post 9/11 age have generated a different sort of friction – in which one person's idea of free expression seems to run smack into the airlines' definition of inexcusably bad behaviour.

Just ask Leisha Hailey, a musician and moderately well known television actor who was thrown off her flight in El Paso, Texas, this week after she kissed her girlfriend and bandmate, Camila Grey, in the seat next to her.

A cabin crew member, apparently responding to a passenger complaint, told Hailey that Southwest was a "family airline" and asked her to stop. By the time Hailey and Grey had stopped swearing and cursing, they were back in the airport, waiting for the next flight.

Southwest later insisted the problem was the abusive language, not the kiss. "The conversation escalated to a level that was better resolved on the ground, as opposed to in flight," it said.

After days of incensed reaction from Hailey, her friends and the lesbian and gay community, however, Southwest backtracked, saying it was offering a full refund for the flight and had "reached out to extend goodwill" – a form of words that fell just short of an outright apology.

Earlier this month, the lead singer of Green Day, Billie Joe Armstrong, was escorted off another Southwest flight in California because he refused to pull up his sagging trousers when asked. "Don't you have better things to do than worry about that?" he retorted. The flight attendant responded: "Pull your pants up or you're getting off the plane."

Armstrong complained, loudly, after he and his companion were taken back to the airport, and Southwest ended up apologising.

He was luckier than Deshon Marman, a college American football player who suffered his own baggy trouser incident on a US Airways flight in June. He ended up in handcuffs, under arrest and charged with trespassing, resisting arrest, and battery on a police officer. The charges were later dropped, and Marman is now suing the airline.

What these episodes have in common is that the affected passengers have all complained loudly and used their fan base to whip up outrage. Advocacy groups have also muscled in. The Gay and Lesbian Alliance Against Defamation pointed out that Southwest is a corporate sponsor and urged everyone to do the right thing. A black advocacy group called Color of Change pointed to the different treatment handed out to Marman, who is black, and Armstrong, who is white, and said it was a clear instance of race discrimination.

"The vastly different treatment of these two passengers underscores the need for greater oversight and training by the airlines," the organisation's executive director Rashad Robinson said.

The airlines, in turn, appear to be running scared from the negative publicity. Kevin Smith, the film director, has not stopped making hay over an incident in February last year when Southwest threw him off a flight, supposedly because he was too fat. Southwest, once again, offered "heartfelt apologies" but also said he had been removed "for the safety and comfort of all customers".