By SIMON ROMERO

SUNLAND PARK, N.M., July 16 - The small airport in this town on the edge of El Paso does more than straddle two countries. As seen by Armando Alarcon, an amateur pilot engrossed in an effort to prevent migrants from dying of thirst on their odyssey across the Chihuahuan Desert, it straddles two worlds.

One world belongs to the Learjets and Citations owned by the Mexican industrial magnates of Ciudad Juárez who keep their planes discreetly and safely tucked away in hangars across the border. Mr. Alarcon's 30-year-old Cessna with its cramped cabin captures another reality on its weekly flights above creosote bushes, extinct volcanoes, a humble fence marking the line in the dirt between Mexico and United States, and, sometimes in surreal slow-motion, migrants on foot reeling from heat exhaustion.

As armed militia-style organizations like the Minutemen Civil Defense Corps call attention to the disarray along the border, Mr. Alarcon has created a group in El Paso called Paisanos al Rescate, or Countrymen to the Rescue, that tries to limit deaths among those who risk everything for a chance at a better life in the United States. About a dozen volunteers in small planes drop bottles of water by parachute to migrants on the desert floor.

"The Paisanos bring a little bit of dignity and hope to a trip that nobody wants to make," said Eduardo Samano, 36, a laborer from the state of Morelos who was gathered with others in a trash-strewn plaza in Palomas, a Mexican town about 50 miles from Sunland Park where migrants often prepare for their journeys. Mr. Samano, who said he hoped to find work cleaning the manure in cattle pens in the Texas Panhandle, had heard of Paisanos al Rescate from reports on Mexican television.

"Do the people in the United States who hate us think we're out here for fun?" he asked.

The plastic water containers that Mr. Samano and others carry when they depart Palomas for their trek across the desert are easily depleted before they reach a destination, often Deming, N.M., about 30 miles away. At least 262 migrants who were crossing the border with Mexico have been found dead since October, a sharp increase from 178 in the comparable period last year, said Salvador Zamora, a spokesman for the United States Border Patrol in Washington. With summer temperatures above 100 degrees, most of the deaths are a result of dehydration and heat stroke.

Mr. Alarcon, 37, who lives in El Paso with his wife and three children, is an unlikely radical in the polarized world of border politics. Slightly pudgy and often clutching a BlackBerry pager, he works as a sales manager for Swift Transportation, one of the nation's large trucking companies, and studied engineering at the University of Texas at El Paso.

But as with many recent entrants into the middle class in El Paso, a city of 680,000 that rubs up against Juárez, Mr. Alarcon's life is a little more complicated. He arrived in the United States as an infant in the arms of his mother as she waded illegally across the Rio Grande, leaving behind her home in Sinaloa in northern Mexico.

He became a United States citizen in his 20's while serving in the Army in the first Persian Gulf war; military officials sped up his American passport so that he could be dispatched to a base in Saudi Arabia as a supply specialist.

Increased vigilance along the border after the terrorist attacks of September 2001 forced migrants to undertake riskier crossings. Mr. Alarcon said he decided to form Paisanos three years ago after the Border Patrol found the body of an 8-year-old girl who had been abandoned in the desert by her smuggler.

"That was our 'go, no-go' moment," said Mr. Alarcon, who started Paisanos with several other volunteers last year after spending more than $80,000 of his own money to buy the Cessna.

The group relies on donations, about $3,000 in cash so far, to cover the cost of aviation gasoline and water bottles. Pedro Zaragoza, a prominent Mexican businessman who owns a dairy and beverage concern in Juárez and Krispy Kreme franchises in El Paso and Juárez, has donated bottles and fuel.

Most of the checks are for small amounts, like $25 from Gail Ann Schultis of Parkville, Mo. "Dear Paisanos al Rescate folks, I read of your recent efforts on a visit to El Paso," she wrote. "I lived there from 1979 to '89 and salute your work."

The group's main pilot is Mario Luna, whose day job is flying the corporate jet for a beer distributing company based in El Paso. Like Mr. Alarcon, Mr. Luna, 39, arrived illegally in El Paso as a child from Mexico. The group has about a dozen active volunteers. Its name is a nod to Hermanos al Rescate, or Brothers to the Rescue, the Cuban-American organization that flew over the Florida Strait in the 1990's to assist people fleeing Cuba by raft.

Though Brothers to the Rescue became an emblem of the anti-Castro politics of South Florida, the Paisanos group tries to avoid politics. Mr. Alarcon shies away from endorsing or criticizing specific immigration policies, saying the group's main objective is to conduct humanitarian missions within an imperfect system. Some advocates view Mr. Alarcon's group as a symptom of the border's woes rather than a solution.

"They're carrying out an act of faith, and it's something we should recognize, but it doesn't go to the heart of the problem," said Fernando Garcia, director of the Border Network for Human Rights in El Paso. "There is no sign the U.S. is prepared to change policies that are killing people on the border. There is a crisis of death resulting from the refusal to recognize the contributions immigrants make to society."

Mr. Alarcon's approach, while too mild for some, has drawn criticism from those who consider it misguided. "We have mixed emotions about what he's doing," said Richard N. Azar, 84, a co-owner of a flight school in Sunland Park. "The Statue of Liberty welcomes these people, but they're breaking the law to enter this country, and that isn't right."

One outspoken member of the Minutemen group in Texas, Wanda Schultz of Houston, said migrants should not be relying on the assistance of Paisanos. "If you don't want to die, don't come," Ms. Schultz, 68, said in a telephone interview. She added that she would give migrants water if they were suffering from dehydration and then turn them over to the Border Patrol.

The Paisanos do not hand over the people they encounter, unless distressed migrants ask them to, a policy that is generally fine with the Border Patrol. Doug Mosier, the public affairs officer for the El Paso sector, said he had no reason to believe Paisanos al Rescate was doing anything other than providing a humanitarian service. "We've given them a phone number they can call if they encounter someone in distress," Mr. Mosier said.

The first bubble-wrapped plastic water bottles dropped last year burst upon hitting the ground, prompting some migrants to curse at the Cessna. Mr. Alarcon solved that problem with the help of a volunteer engineer from California who suggested using the small surplus parachutes that the Army uses for nighttime flares. The white parachutes now carry a silk-screened message in Spanish - "God blesses you" - and the telephone numbers of Mexican and Salvadoran consulates.

Some evenings Mr. Alarcon drives into Mexico to talk to the migrants preparing their cat-and-mouse trip.

"The senselessness of it all can get to you, all the money being spent to harass people who want to be our maids and gardeners," Mr. Alarcon said. "It's as if the Cold War were being fought again with the Mexicans as the bad guys. If the tragedies here weren't so common, this would feel like my own version of Spy vs. Spy."