A pilot and a doctor? Yes and no.

MILWAUKEE - He seemed like Superman, able to guide jumbo jets through perilous skies and tiny tubes through blocked arteries. As a cardiologist and United Airlines captain, William Hamman taught doctors and pilots ways to keep hearts and planes from crashing.

He shared millions in grants, had university and hospital posts, and bragged of work for prestigious medical groups. An Associated Press story had him leading a team training session last spring at an American College of Cardiology convention.

But it turns out Hamman, 58, isn't a cardiologist or even a doctor. The AP found he had no medical residency, fellowship, doctoral degree or the 15 years of clinical experience he claimed. He attended medical school for a few years but withdrew and didn't graduate.

His pilot qualifications do not appear to be in question: he holds the highest type of license a pilot can have, a Federal Aviation Administration spokeswoman said. However, United grounded him in August after his medical and doctoral degrees evaporated like contrails of the jets he flew.

He resigned in June as an educator and researcher at William Beaumont Hospital in Royal Oak, Mich., after a credentials check revealed discrepancies, a hospital spokeswoman said.

Doctors who worked with the pilot are stunned, not just at the ruse and how long it lasted, but also because many of them valued his work and were sad to see it end.

Even after learning of Hamman's deception, the American Medical Association was going to let him lead a seminar, altering his biography and his title from "Dr." to "Captain" on course materials. It was canceled after officials found out.

Now, groups that Hamman worked for are red-faced that they hadn't checked out the tall, sandy-haired man who impressed many with his manner.

Journals that printed articles listing Hamman with M.D. and Ph.D. degrees are being contacted in case they want to correct the work.

Hamman, who lives in Michigan and is based in Chicago, did not return several phone calls and e-mails seeking comment.

There is no indication Hamman ever treated a patient, though his teamwork training had him videotaping in emergency rooms and elsewhere where patients were being treated.