Lew Emery remembers all too well the time a Canadian man woke him with a midnight phone call: His son-in-law was dying in Mexico and needed to be transported to the Western Ontario University Hospital, the only place a potentially redeeming operation for a basalskull aneurysm could be performed.

The next morning, a $2 million Learjet outfitted as an ambulance left the airport here at 5 a.m. and had the patient in Canada by midafternoon. The following day the patient's father-in-law called Emery to report that his son-in-law was on the road to recovery.

Imagine calling a perfect stranger at midnight in another country," the man said to Emery.

"actually, it happens quite often," said the 69-year-old pilot, whose five jet ambulance fleet is unique in the world. It is available any time, on a few hours' notice, to haul patients anywhere in the Western Hemisphere: wealthy heart-attack victims stricken in the Caribbean, carried to the Mayo Clinic in Minnesota; corporate officiers ferried from one hospital to another closer to home; fire victims whisked to a Texas burn center, and, increasingly, the transportation of vital organs, particularly kidneys. "One of the great ironies in this business," says Emery, "is that the FAA is more careful about a can of gas additive that you put in your fuel tank than it is about patients. Virtually anybody can take a battered-up single-engine plane and call it an ambulance. The thing we rely on most is our reputation."

Hospitals, airlines and insurance companies -- including Western Ontario University Hospital, American Airlines, Eastern Airlines, Pan Am, State Farm and Travelers -- regularly recommend Emery's Airborne Intensive Care Service for patient transport. The company has carried the daughter of a former prime minister of Iran, Guy Lombardo's manager (from the Grand Cayman Islands to San Diego), dozens of celebrities who won't allow their names to be revealed, as well as hundreds of patients either wealthy enough to afford this service or fortunate enough to have insurance that will cover transportation as costly as this. Emery charges $1.80 a mile; a one-hour, 45-minute flight from Washington to Chicago, for instance, now runs $2,445.55. (The customer pays for the plane both ways.)

For every hundred patients Emery agrees to transport, there are a few refusals.

"I had the rare distinction of refusing to transport Howard Huges on his final flight from Mexico back to the United States," says Emery, "because his doctor wouldn't provide enough details on the mission in advance. I'm not sorry I turned that one down, either. We're really supposed to believe he died just minutes after crossing the border into Texas? Who needs those international legal problems?"

Emery bagan his air ambulance service five years ago as an adjunct to his Emery Air Charter, which ferries corporate executives and private individuals around the country.

"We won't carry rock groups," says Emery, "because one whiff of those funny cigarettes at altitude and it's like the pilot had a stiff drink."

Although it is spelled identically, the company has no connection with Emery Air Freight, the small-package air delivery service.

Airborne Intensive Care operates from a large hanger at this suburban airport, 90 miles west of Chicago. There are cabinets full of special life-support equipment, including the only air-worthy respirator in existance and an Air-Vac heart monitor, which transmits EKG signals to any hospital on the ground via a radio telephone link. The only similar unit is aboard Air Force One.

The jet ambulance interior looks much like any hospital intensive-care unit room: a bed running down the length of the fuselage against one wall, with jump seats for two nurses and a doctor. (One specially trained nurse goes on every "Lifegrard Flight," as the FAA terms such medical mission, which have absolute priority in taking off and landing.) Respirator, EKG unit and intravenous sets are bolted alongside the bed; there are also seats for two members of the patient's family, in addition to the two pilots required to fly the plane.

"We used to have one regular patient," says Emery, "who had emphysema so bad that he couldn't walk across the street without his oxygen. Every year we'd fly him down to Florida for his vacation."

Emery tells scores of stories: A patient going from Baltimore to San Jose for his second heart transplant, with pneumonia so bad that the plane had to stop in Nebraska for extra oxygen; a ferry from Washington to Columbia that required overflying Cuba (permission granted in a matter of hours); cerebral hemorrhage patients who need to have sea-level pressure maintained in the cabin, thus forcing the Lears to fly at half their normal 45,000-foot altitude.

Emery became fascinated with aviation 20 years age, at the age of 50, when he ran a motorcycle importing business and discovered that the time saved by flying privately could radically increase profits. Eventually he realized that air-charter work could be more profitable than sales, and started Emery Air Charter. At 65, he became the oldest pilot every certified to fly Learjets.

"Actually I don't fly them for paying customers," he says. "I have 15 pilots on my staff. But sometimes, if it's a slow day and a plane needs to be ferried somewhere, I'll get in the left seat. Flying a hot plane like this remainds me that I'm still pretty healthy."