Button was flying tail-end Charlie in a three-plane formation over Arizona on a sunny April morning two weeks ago, just about to drop that first 500-pound bomb, when he suddenly broke formation and headed northeast, toward Colorado. He failed to answer radio calls or flick a switch that would have made his plane easy to track on radar. In northern Arizona about 20 minutes later, some schoolboys saw the A-10 poke down through the clouds, bank into a half-circle and then disappear again. Flying straight to ski country around Aspen, Button’s plane began to zigzag until, at about 1:40 p.m., it fell off the radar screen for good. Air force officials estimated that Button had at most a minute or two of fuel remaining. About 20 skiers in the area heard a loud explosion. Late last week helicopters and small aircraft, as well as a U-2 spy plane capable of seeing through clouds, crisscrossed the mountains looking for wreckage, but heavy snowfall hindered the search.

On the ground, the air force tried to solve the mystery of why Button had flown off. There were no immediate clues. Flying jets seems to have always been his purpose in life. His father, an air force veteran of World War II, Korea and Vietnam, taught Button to fly before he could drive. At his technical college in New York, the young Button liked to parade around in his air force ROTC uniform. He quoted General Patton under his yearbook picture: “Self-confidence and leadership are twin brothers.”

Button was a good, but not great, pilot. Top guns get to fly the glamour planes, the F-15s and F-10s. The A-10 is so slow and ugly that pilots call it a warthog and joke about it getting rear-ended by a bird. But the plane is heavily armed and very maneuverable-perfect for flying through mountain passes. Unlike flashier fighter planes, the A-10 can land almost anywhere. Predictably, conspiracy theorists began spinning plots: Button had landed his A-10 in the mountains and hidden in a bunker-to attack the federal courthouse where Tim McVeigh is on trial. Or to avenge Waco on April 19. Or to bomb Boris Yeltsin at the Denver Economic Summit scheduled for this June.

Investigators are grilling his fellow pilots to find out if Button belonged to a militia. But his neighbors describe him as having amiably chatted at barbecues and listened to Mozart as he read World War II flying histories in his meticulously kept apartment, a restored 19th-century cavalry quarters at Fort Clark, Texas. He seemed to have plenty of buddies, though apparently no girlfriend. “I’ve got to find a woman who loves airplanes and motorcycles,” he explained to Mrs. Pingenot. He suggested he might “find a Fraulein” in Germany, his next posting. There were rumors that Button was upset because his mother had recently become a Jehovah’s Witness–a proselytizing Christian sect. But in fact his mother has belonged to the faith for years. His parents said they had left their son in “good spirits” after having a “wonderful time” with him only six days before he vanished. Button had rented a car for his parents’ sightseeing trip to the Grand Canyon, complete with a tape of favorite show tunes like “The Sound of Music.” Rereading the letter from Button–written three days before the pilot flew off–Ben Pingenot just couldn’t square the happy warrior he knew with a man consumed by a death wish. “Maybe,” he told NEWSWEEK, “it’s what Mark Twain said about every man being a moon, and has a dark side he doesn’t let anyone see.”

As the air force combs the Rockies in search of a lost attack aircraft, it is also wondering what prompted Capt. Craig Button to flee a routine training run on April 2. The events of that day:

1 Three A-10 Thunderbolts, or Warthogs, leave Davis-Monthan Air Force Base for a training bombing run. Each is armed with four 500-pound bombs.

2 The squad does an aerial refueling and continues, heading toward a nearby bombing range.

3 Captain Button, last in a single-file formation, suddenly leaves the pack and heads northeast toward Colorado.

4 Nearly 800 miles later, Button’s plane disappears from radar. Skiers near Vail report hearing a crash and seeing smoke.