Los Angeles, California (CNN) -- Southwest Airlines apologized a second time Monday to film director Kevin Smith for pulling him off a Saturday flight because of his size.
"We're very sorry for how his night unfortunately played out," Southwest said in a written statement.
The airline said it "could have potentially handled our communication better," but defended "the determination that Mr. Smith needed more than one seat to complete his flight comfortably."
The controversy is a public relations challenge for Southwest. The airline had the lowest rate of passenger complaints among U.S. airlines last year, according to a government report issued last week.
Smith -- known for his movie character "Silent Bob" -- began posting a barrage of angry messages on the online network Twitter, where he has 1.6 million followers.
He vowed in a recording posted on his Web site to "scorch the earth" with his complaints against Southwest.
"Dude, I know I'm fat," Smith said. "That's not why I was truly thrown off that plane because I fit perfectly in the seat."
Smith said he had no trouble buckling his seat belt and lowering his armrests.
"I am not fat enough to eject off a Southwest flight," he said.
He said he suspected he may have been bumped by an airline employee who did not like his comic films, which include "Zach and Miri Make a Porno," "Clerks" and the upcoming "Cop Out."
His goal is to force Southwest to change the way it deals with overweight passengers.
Southwest said it is listening.
"We want to assure everyone that has expressed concern over the situation that we will use this experience in our customer service program when training our employees on the correct way to apply the policy," the airline said.
The "customer of size policy" implemented 25 years ago requires "passengers that cannot fit safely and comfortably in one seat to purchase an additional seat while traveling," it said.
"If a customer cannot comfortably lower the armrest and infringes on a portion of another seat, a customer seated adjacent would be very uncomfortable and a timely exit from the aircraft in the event of an emergency might be compromised if we allow a cramped, restricted seating arrangement," the airline said.
"I can buckle that seat belt and that is a hallmark for any fat person," Smith said.
Smith did purchase two seats for the flight to Burbank, but he was allowed to board an earlier flight as a standby passenger, and only one seat was available on that flight.
The extra seat is not a necessity, he said, but a luxury because "Southwest flights are cheap."
"I'm flying on the welfare airline, food-stamp airline," he said. "So I think I can indulge myself with two seats, and I can afford to do it."
Although Southwest said airline executives have personally called him to apologize, Smith insisted Monday afternoon he's not gotten a call.
Although he bought 10 tickets on the airline in just the past week, he said "I'm never going on Southwest again."