Boss, Mo. ? An Air National Guard F-15C crashed Friday in rural south-central Missouri after the pilot ejected, authorities said.

The pilot was flown to a St. Louis hospital and was in serious condition, a hospital spokeswoman said.

The fighter jet crashed in a wooded area near Boss. The state highway patrol said no buildings were hit and no one on the ground was injured. The pilot is a 10-year veteran of the guard. His name and rank were not immediately released.

“When medical personal reached (the pilot), they reported he was alert, he was conscious and he was able to an answer questions,” said Steve Lawhead, a Dent County sheriff’s deputy.

The F-15C Eagle crashed on private property surrounded by Mark Twain National Forest.

“I heard something fluttering, like something was wrong with the plane,” said property owner Dairl Asher, 71. “I heard a bang and I saw some smoke.”

Ted Pryor, 34, and David Major, 39, saw the plane circling, got into a truck and went to the site of the crash, then called authorities.

“You could tell he was scared,” Pryor said of the pilot. “He kept saying, ‘I feel like I’m going into shock.”‘

The one-seater plane, a 1980 model worth about $40 million, was from the Missouri Air National Guard’s 131st Fighter Wing, based at Lambert-St. Louis International Airport.

Col. Robert Leeker, commander of the 131st Fighter Wing, said the plane was among four that engaged in one-on-one training fights in which speeds of 400 to 450 mph are typical. The other planes returned safely.

“If you can envision the old-style dog fight, this was it,” he said during a news conference. “Two airplanes go out and start fighting each other.”

Leeker declined to speculate on what might have caused the accident. There was no contact between the downed plane and its partner in the mock fight, he said.

He said a video recorder was in the cockpit of the crashed aircraft, but he didn’t know whether it was recoverable.

An Air Force investigative report is due in 60 days.

Another Missouri Air National Guard fighter crashed in May after taking off from Lambert. That fighter, an F-15D, had been conducting drills about eight miles south of Vincennes, Ind., when a jammed cable caused it to crash, according to an Air Force report released last week. The report said the crossover cable was properly installed, inspected and maintained, leaving unclear why it malfunctioned.

The pilot ejected and had only minor injuries. No one on the ground was hurt.