When it comes to travel, there’s airline time, and then there’s actual time.

It’s an alternate reality that Evan Myrianthopoulos learned about on a recent American Airlines flight from Los Angeles to JFK. The New York-based executive checked in early for his transcontinental flight and then strolled over to a newsstand to catch up on some reading. When he came back, nine minutes before the flight was scheduled to leave, gate agents had already closed the door and wouldn’t let him board.

“But the plane was still there,” he remembers. “I said, ‘What’s going on here? Can you open the door and let me on the plane?’ The agent said he needed to check with the pilot. A few minutes later, the plane pulled away. I couldn’t believe it. I was shocked.”

Myrianthopoulos wasn’t the victim of an overzealous ground crew or a coldhearted pilot, as you might suspect. Instead, his plane left early because of a focus group.

“Our own customer surveys continually show that travelers are much more concerned about an on-time departure,” says American spokesman Tim Smith. “Think about your last trip – the moment you feel the aircraft start to back off the gate, what do you see most the people around you do? They look at their watch and make mental note of whether they’re leaving on time or nearly so. I know I do it, and I see those around me doing the same.

“Those same surveys tell us customers feel on-time departure is most important because it at least gets them going on schedule and usually results in a decent arrival time, too.”

Sure enough, American’s leave-early policy out of LAX is paying off. Of the four major carriers to service the west-to-east route during the last two years, American flew the most flights per week, and its flights arrived an average of three minutes early, according to the U.S. Department of Transportation. Flights by TWA and United arrived in New York an average of five minutes late, while Delta’s arrived an average of almost eight minutes late.

All well and good, but, when an airline says its flight leaves at a given time, what does that mean now? That the doors close at the stated departure time, that they may close at any moment after the check-in deadline (generally 10 minutes before departure for domestic flights, 30 minutes for international flights)?

I asked the DOT to comment on this apparent rift in the time continuum. Don Bright, the Bureau of Transportation Statistics’ data administration chief, says his agency requires airlines to report departure and arrival times. The government also mandates that airlines notify passengers when they must check in to make the flight.

Just because a flight is scheduled to depart at a given time doesn’t mean the crew has to keep the doors open until that point, says DOT spokesman Bill Mosley. “We would not consider it deceptive if the carrier left after its check-in deadline,” he says.

Translation: Airline time is OK with Uncle Sam. What’s not OK is how American handled the Myrianthopoulos incident.

American, for its part, didn’t want to talk about it.

“I have no specific knowledge of the incident cited by your reader,” says Smith, “and have no desire to debate what may have happened and who said what to whom that day.”

Myrianthopoulos says he got the runaround from American when he tried to find out why it wouldn’t let him on the plane.

“The staff said that there were signs at the gates saying that boarding closes 10 minutes prior to departure,” he says. “But there were no signs anywhere.”

An airline supervisor refused to rebook him on a Continental flight to New York which left an hour later, so Myrianthopoulos had to wait six hours at LAX for the next American flight – the redeye. To make matters worse, he had to attend a board meeting the following morning.

“I got one hour of sleep that night,” the irritated executive says, adding, “I’ve told my travel agent that I’m never going to fly American again. They don’t care about their passengers.”

Perhaps American Airlines could have handled his grievance more competently. But it’s tough to argue with a carrier when it’s doing what its passenger surveys tell it to do, even if it means running the clocks a little early and leaving some of us behind.

I guess travelers should be careful what they ask for.