NEW YORK >> Ever wonder how airlines decide who gets a seat upgrade on flights? Airlines say it’s strictly by the book: Loyal customers are rewarded based on their status in frequent flyer programs.

But some flyers insist that once in a while, they get upgraded even when they’ve bought the cheapest seat.

AirfareWatchdog.com founder George Hobica acknowledges that “upgrades mostly go to people with status in the program. If you’re silver or gold on British Airways or United, and they have to upgrade people because they’ve oversold economy class, the first thing they do is go down the list of (who has) status.” But he says he’s also been inexplicably upgraded when he was “wearing a nice suit and tie” and other passengers were “looking like Richard Simmons.”

A number of airlines contacted for comment said it never works that way.

“The list is the list and the gate agents work the list,” said American Airlines spokesman Josh Freed, referring to the “list of customers who potentially qualify for upgrades based on elite frequent flyer status.” Gate agents, he stressed, are “not out there putting who they like, or who’s best dressed, further up the list.”

Alaska Airlines spokesman Cole Cosgrove agreed, saying upgrades go to elite members of the airline’s mileage plan. If you’re not a member, the only way to get an upgrade on Alaska is by redeeming miles, using a guest upgrade code given to the airline’s “MVP gold members,” who are permitted to share the codes with friends or family; or by paying for an upgrade at the gate ($50-$200, depending on length of flight).

Other airlines, including Delta and United, also said their agents are bound by upgrade policies as described on their websites. And yet, there are people who say they’ve gotten upgrades without status.

“To those people who say, nonsense, this can’t happen, I disagree wholeheartedly. This has happened to me from coach to business class a number of times,” said Ann Lombardi, a business English teacher and tour organizer at The Trip Chicks. What’s her secret? “I just smile and say thank you for your help. I might tell a little story about myself. It may be the combination of being nice, dressing decently and the luck of the draw.”

She got a surprise upgrade earlier this year flying on Emirates. “I was just standing in line, I got to boarding, the woman pulled me aside and gave me my boarding pass and it said 1B,” she recalled. “I said, ‘Is there an extra digit left out (on the seat number)?’ and she said, ‘No, we decided to upgrade you.’” The upgrade to first class from coach put her in a private compartment. After a knock on the door, she was asked, “Would you like Dom Perignon and black caviar now or later?”

Kim Curtis, a content strategist for a bank in San Francisco, says she’s been upgraded even though she always buys the best airfare deal she can find. “I always give the gate agents and the ticketing agents compliments,” she said. “I know it sounds corny but I figure they deal with a lot of difficult rude people so I try to be the exact opposite of that.”