Early in May, 4-month-old Andrew Meyer flew from Texas to Baltimore on a wing and a prayer, in a Cessna 421C that carried a plaque dedicating it to "the Lord's service." Andrew was a baby who was expected to die.

The Arlington, Tex., infant landed at Baltimore-Washington International Airport, cradled in a 250-pound respirator, under the care of a group of high-technology good samaritans called the Washington Aviation Ministry.

This unusual volunteer organization, which airlifts about 20 patients a month and is financed by donations, had flown Andrew for an emergency operation at Johns Hopkins University Hospital. The surgery would try to correct the effects of a fatal genetic condition related to dwarfism. A compressed spinal cord was threatening his ability to breathe.

The infant's flight was the latest in a series of dozens of mercy missions undertaken in the Cessna since 1985 by a group of 110 volunteer pilots, flight nurses, doctors and assistants. Their efforts help families who otherwise could not use or afford commercial air ambulances which, in the Meyer family's case, would have cost $10,000 to $12,000.

Among others, the eight-seat plane has carried Glenn Richard Anderson Jr., brother of Mideast hostage Terry Anderson, home to Florida to die; it delivered Eyal Sherman, a 5-year-old with a brain stem tumor, to a doctor in New York City who saved his life; it brought 89-year-old Mary Kennedy, frail and unable to walk or eat, home to New Jersey for care.

The nonprofit air ministry, which is in the process of changing its name to Mercy Medical Airlift, was recently honored by county and city volunteer offices here for its work, which amounted to more than 6,000 hours of service last year.

"Aviation is a part of my life that gives honor and glory to the Lord," said one of the organization's volunteer pilots, Click Smith, a retired Air Force major general and former combat pilot. "I feel like what we're doing is a ministry . . . . I pray with my passengers; I try to lift them up.

" . . . we're not trying to compete" with commercial air ambulances, he said. "There are just so many people who don't have the money."

Andrew Meyer's parents, Stephen and Mary Ann Meyer, pledged that they and their friends and fellow church members would try later to raise money to cover the volunteer group's fuel bill, estimated at $4,800.

And so on May 30, after the delicate surgery and several weeks of recovery, Andrew Meyer was flown back to Texas to get on with his life. He is now "a child who is expected to live," said Stephen Meyer, 27.

The Washington Aviation Ministry, motivated by an interest in Christian service, began in 1977 as a volunteer air transport organization for church workers and missionaries. The organization now concentrates on helping the terminally ill, newborns in critical condition, people who have been injured far from home and elderly patients who need to be reunited with their families.

The ministry's three small planes fly out of Montgomery County Airpark in Gaithersburg, undertaking about 20 missions a month in and out of a 13-state area from Virginia to the Canadian border. Theirs is the only charitable air service available for all types of medical emergencies in this region, and one of only a few volunteer medical air transport organizations in the country.

The estimated $636,000 needed to run the service in the coming fiscal year will have to be raised largely through donations from individuals, corporations and foundations, said Edward R. Boyer, the group's president who is also an administrator at the Department of Health and Human Services. Families end up paying for about half the direct costs, he said; pilots and other volunteers keep the service running with monthly infusions of cash, and suppliers often sell fuel and services at a discount.

Because medical insurance typically does not pay for emergency transport, and there are no provisions for it in federal or state law, demand for the air services is high, ministry spokesmen said.

"As soon as people hear about it, they come running," said the Rev. Louis Evans Jr., senior pastor at National Presbyterian Church and one of the organization's founders.

"I feel pretty positive after one of these flights, said Sherry Brenneman-Bell, a volunteer nurse who also works at Washington Hospital Center. "I always get a sense from the families that we were a last resort."

The flight service is important because, increasingly, medical specialties are available only in certain regions, said Boyer, a founder of the ministry. The New York surgeon who saved Eyal Sherman's life, for instance, is a specialist in brain tumors in children. The boy's father, Rabbi Charles Sherman, said he was told that Dr. Fred Epstein was his son's only chance.

In the Washington area, Children's Hospital National Medical Center treats babies from throughout the East Coast with its heart-lung machine, said Dr. Marilea Miller, director of neonatal transport for the hospital. The air ministry has delivered two infants to the hospital in the past month.

"Insurance companies make it very difficult for families" who need to move ill members, Miller said. "They fail to recognize that transportation is a valid medical need for a patient."

Sherman said that when he asked Blue Cross/Blue Shield to cover the cost of his son's flight to New York, the insurer told him "that they should have not even paid for ambulances to and from the airport, that it was not an emergency, even though this was the only man in the world who could do the surgery."

Sherman, who heads one of the largest Jewish congregations in upstate New York, described flying with the air ministry as "a religious experience."

"They really do God's work," he said. "They expected nothing in return," only "what you would be able to pay them."

Before the flight took off from Syracuse, Sherman said, "The pilot turns around to me and says, 'Would you mind if I pray?' I looked at my wife, and she looked at me. But it was a very comforting kind of thing. When you're hurting, prayer is a source of comfort.

"These people were wonderful. They really understood our situation. They were not there to proselytize -- they understood that I was a Jew," the rabbi said. After they landed, and an ambulance took their son away, the crew told the Shermans that they would pray for the youth, he said.

As demand for the emergency services spreads, the air ministry is attempting to clone itself elsewhere. Two services have been started, in Southern Illinois and Houston, and two others are in the works, in Atlanta and Miami, Boyer said. Because the air ministry organization is not in the charter business, it does not need to be chartered by the Federal Aviation Administration, Boyer said.

Smith, who served as vice director for logistics for the Joint Chiefs of Staff, echoed what many of the air ministry volunteers say about their work: It is an extension of their religious beliefs.

Some of the volunteers also are interested in building up their air time and acquiring high FAA ratings as pilots, he said. They also share a passion for planes, he said.

"Flying is the major part of my life," the former test pilot said. "It's what I'm all about." In Vietnam, where he survived being shot down, he realized "that the Lord really had something else for me to do . . . . "

"I'm your pilot, Click Smith," he says by way of introduction to passengers: "I've got 29,000 hours of flying time; besides that, the Lord is with us."