Los Angeles International Airport -- Just off the end of runway 25L here, pilots and mechanics" target="_blank" title="n.力学；构成法；技巧">mechanics sleep in recreational vehicles in an employee parking lot. These are their at-work crash pads. After putting in their shifts over several days, they fly long distances to their more permanent homes and families -- in places like Utah, Wisconsin, Texas and Hawaii.

It's a quiet community with no parties, outdoor beer drinking or gaudy flamingo decorations or lawn chairs allowed. When it's time to go to work, they walk to a shuttle-bus pickup. 'We're just a bunch of professionals living away from home, doing the best job we can and being safe at the job,' said Steve Young, an airline mechanic who lives part of each week in an RV.

Commuting by airplane is a long-standing and, some say, necessary practice for this cash-strapped industry. Economic turmoil in the industry has spurred more pilots, flight attendants and mechanics" target="_blank" title="n.力学；构成法；技巧">mechanics to commute as vast schedule changes have moved jobs around the country. Instead of relocating families, many aviation workers -- half of all pilots by some counts -- simply commute to work by airplane.

They can hitch free rides on flights of their own airline or, in many cases, those of competitors. Most share cots in cramped apartments with other commuting workers to avoid the expense of hotel rooms. All are expected -- and indeed required by federalregulation -- to show up to work well-rested, no matter how taxing the commute.

'It's the dirty secret of the airline industry,' said one airline chief executive, who asked not to be named. His U.S. airline has pilots who commute from as far as South America.

Long-distance commuting has raised safety concerns about whether flight crews are indeed reporting for work rested and ready. On Feb. 12, 2009, both pilots of Continental Connection 3407 had long commutes before reporting to Newark, N.J., where they began work. They may have rested only on couches in an airport crew room before crashing near Buffalo, N.Y. The National Transportation Safety Board ruled the crash, which killed 50, resulted primarily from pilot mistakes.

The captain, who lived in Tampa, Fla., apparently spent the night before the accident in the airline's crew room. The first officer traveled all night on the day of the accident from Seattle on cargo flights. Investigators said neither pilot had any overnight accommodations in Newark. (Sleeping in the crew room is against most airlines' policies.)

Airlines typically have five or 10 cities where they establish crew 'bases'-- that's where trips begin and end for pilots and flight attendants. Each month, the schedule of flights from a base can change. And each month, the crews assigned to that base can change.

Pilots and flight attendants request schedules they want and are assigned based on their seniority.

Schedule cuts through the recession have meant lots of shifting between bases-- a few bases were closed, and most shrunk, forcing some workers to change bases.

Some commute to avoid uprooting family when airline jobs move. Some opt to live in states without state income taxes and fly to work. Some workers choose to shift bases to get a preferable schedule or higher pay.

And the airline lifestyle lends itself to commuting. Pilots and flight attendants often work long days and then have several days off. Since they are on the road anyway for their working days, they often aren't sleeping at home anyway. So they commute for a four-day trip, then fly home for a few days.

Regional airline employees have a particularly difficult challenge-- they earn far less than pilots and flight attendants at major airlines, and their airlines shift planes and routes around frequently.

'When you're making below $30,000 or $40,000 a year, how much money can you afford to spend on a second home at a base?' asks Air Line Pilots Association President John Prater, a Continental Airlines Inc. captain who, during his flying career, lived near St. Louis and commuted at different times to work in Houston, Newark, Honolulu and Guam.

But there's little doubt that commuting long distances has become more taxing. With planes so full in the past couple of years, pilots and flight attendants say they have trouble getting an empty seat for a free ride since they often are at the bottom of standby seating lists.

To help, Los Angeles World Airports, the city agency that runs LAX, decided in 2005 to let airline workers live in mobile homes and campers in an airport parking lot. (It is likely the only such officially sanctioned airport community in the country.) The village, located in a corner of Lot E, is limited to 100 vehicles. Five are currently on the waiting list. Vehicles have to be certified every six months that they can actually move; they pay $120 a month to park.

Residents say their airlines told them they couldn't be identified by name or airline in articles about the parking-lot village after a story about the place ran in the Los Angeles Times last July.

One pilot who lives in Texas and commutes to a trailer in Lot E says the camper is simply 'a place to come and get ready for work.' He often flies to LAX the night before his work schedule begins and sleeps in his 1979 RV, where he keeps his uniforms. And when his flying schedule is done, he typically ends up at LAX late in the day -- too late to catch a flight back home.

Rather than a hotel room, which he says he can't afford, or an inexpensive shared apartment, he enjoys his camper, wearing ear plugs at night to sleep through the noise of jets overhead.

'I never thought I would be here, but pay cuts force us to be frugal,' he said.

Mr. Young, the airline mechanic, is a leader of the commuter community's association, called Airport Employee RV Organization, or AERO. He negotiates with airport officials and has an agreement with his boss that he can be named as long as his airline isn't identified.

Since the airport doesn't provide electrical or water hook-ups, residents have to improvise. Mr. Young uses solar power for electricity during the day and a small generator at night. His RV has a 100-gallon water tank that provides about eight days' of showers. The airport doesn't allow a propane truck to service the RVs, so residents have to drive 12 miles to fill propane tanks.

The RV community, he says, enhances safety and job security for commuters. 'This is all about being at the job and being well-rested,' Mr. Young said.