As I settle in for my flight, my seatmate pulls out a magazine. I pull out something else entirely: my very own airline-endorsed exercise equipment.

When the pilot says it's safe to move about the cabin, I take him seriously. I remove a resistance band and a small rubber ball from a pocket-sized kit and get to it.

As I step on the middle of the band and pull the ends back with both arms, the woman next to me says nothing. Five minutes earlier, she had been chatting nonstop, telling me about her trip, her husband, her frustrations with her job. Suddenly, she is very focused on her magazine. She does not acknowledge, even in the slightest way, that I am starting a series of knee lifts while seated in my window seat.

I catch a curious sideways glance from the fellow at the end of the row. I smile, place the ball between my knees, and lift my legs. He looks away nervously.

My workout routine may be unusual, but some officials for low-cost airlines Song and JetBlue hope the concept will take off. It's the latest twist on a move that started years ago with efforts to keep passengers from developing blood clots during flights. But now we're not just talking discreet ankle twirls, but chest presses (from Song) and liberal adaptations of yoga and Pilates (from JetBlue), all in the confines of your seat.

The primary motive is entertaining passengers, not reducing liability, insists JetBlue spokesman Bryan Baldwin.

"It has nothing to do with liability concerns," said Baldwin. "We're always looking for something to make our flights more interesting for our passengers."

Song spokeswoman Katie Connell agrees that helping passengers avoid deep vein thrombosis, a rare but potentially deadly condition that can occur when blood clots form in the legs as a result of prolonged sitting, "was not our intended purpose in creating this. We see it as a good option for staying fit while on the road."

That may be a stretch, say some fitness experts. "To call them fitness programs is a little liberal," said Cedric Bryant, chief exercise physiologist for the American Council on Exercise. Exercise physiologist Michael Bracko, a spokesman for the American College of Sports Medicine, finds some benefit to the activity, but he questions its practicality.

"As a person who flies a lot, I would say it's often hard to move on planes," said Bracko. "I don't know how other airlines would be able to implement this unless [passengers] are doing it in the aisles. On a flight I took recently, I couldn't even cross my legs. How do airlines expect people to be able to do this?"

And then there's another question: Will people want to?

'Weirdo' Moves

Another motivation for the programs: generating publicity for new carriers like Song, an offshoot of Delta Airlines.

The airline hired high-profile New York trainer and gym owner David Barton to develop and plug the high-altitude exercise program, with its $8 exercise kit. Barton, a spike-haired bodybuilder with the physique of a 1970s-era Arnold Schwarzenegger and the cosmopolitan nerdiness of Austin Powers, has won national attention with his gym's slogan, "Look better naked." Since the Song exercise program debuted in July, Barton has been touting it along with "Bachelor" TV show star and New York Giants quarterback Jesse Palmer.

Barton says he developed the program from one that he did while traveling. And he swears the routine is safe in midair. He's never popped a fellow passenger with a stray resistance band or knocked anyone with an errant ball.

The JetBlue programs also were created with the help of big-name fitness experts. Crunch Fitness, a national chain of gyms, developed the routines when JetBlue was searching for a way to distinguish itself from other low-cost carriers.

JetBlue seems to recognize the entertainment value of its endeavors. The airline's yoga cards are subtitled "how to look like a real weirdo to your fellow passengers." One of its moves calls for passengers to straighten their hands above their heads. "A flight attendant may ask you if you need something," the card warns. "Tell them that we all need inner peace."

"Will people do it on the plane?" Barton says. "I don't know. If someone's not an exercise person at all, they're probably not going to want to do this." Assuming a commitment to fitness, however, he said, "If you don't have access to a gym, this is the next best thing."

Maybe. The cramped quarters on most planes, along with the humiliation factor, make it difficult to do the exercises comfortably. The moves require enthusiasm not only from the person doing the routine, but cooperation from the people nearby. Even on the slightly roomier Song aircraft, doing the exercises can be tricky, I found.

Take the chest press exercise in the Song routine. You're supposed to squeeze the little ball between your palms, which you hold in a praying position in front of you. Then you extend your arms straight out. You do this -- back and forth, arms in, arms out -- 10 times. And that's nothing compared with some of the JetBlue "Flying Pilates" exercises. One of its moves calls for passengers to raise their arms to the ceiling and "make a swimming flutter motion with the arms as you continue to lift your chest to the ceiling."

Even among the younger flyers that the airlines hope to attract, there are skeptics.

"It's ridiculous," says Washington resident Chris Holt, 29, a recent passenger on an Albany-to-Baltimore flight.

Said Jay Piliponskiy, 27, who flew solo on the same flight, "I just want to chill out and read."

Flight of Fancy?

Despite such reactions, the airlines are betting that many passengers will get on board with the idea. If the Song kits are popular during a testing period through August, the airline expects to offer its customers -- all of whom have TV monitors at their seats -- a video demonstrating the moves on one of its television channels.

JetBlue started outfitting each seat in May 2002 with a pamphlet showing travelers how to do yoga in their seats. This year, the company introduced the Pilates routine, which will eventually replace the yoga moves.

Pilates? Come on.

Baldwin holds firm.

"We would consider these to be Pilates," Baldwin says. "Of course, they're specifically designed Pilates moves that can be done in your seat. You're not going to be on a mat on the floor, but it's different moves that we've selected with Crunch Fitness to provide relaxation to passengers."

Baldwin says his airline will continue to look for new opportunities to energize its flights.

Barton remains bullish, too. Any awkwardness people might feel about doing biceps curls in front of other passengers will fade in time, he predicted.

"It might seem different because people haven't seen other people doing it yet," said Barton. "But it's one of those things people will become accustomed to. If they had never offered cocktails on the plane, would someone feel comfortable pulling out a flask? But if they offer it to you, you might try it."

*

Rebecca Adams covers health care as a reporter for Congressional Quarterly.

A vampy brochure dispensed by Song Airlines illustrates a biceps curl exercise with a resistance band at 30,000 feet. Above, a JetBlue exercise instruction sheet, developed with the help of Crunch Fitness, illustrates in-flight "core-strengthening moves" involving arm flutters and chest lifts. Another page reads: "How to look like a real weirdo to your fellow passengers." At left, Song Airlines' $8 on-board exercise kit, featuring a program developed by New York trainer David ("Look Better Naked") Barton.