A small civilian plane flying erratically crashed into a field in Indiana Wednesday as two F-16 jets tracked its path, U.S. military officials said.
The military doesn't suspect terrorism, but officials believe the pilot passed out after suffering from a lack of oxygen.
The Federal Aviation Administration called the U.S. military to send the fighter jets after the pilot stopped responding to their radio communications, according to the FAA's Web site.
The plane went into an uncontrolled spin near Muncie, Ind., and crashed in a swampy area on a swath of farmland, the FAA said.
U.S. Northern Command spokesman Michael Kucharek said the pilot was the only person on the plane and may have lost consciousness due to a condition called hypoxia.
Kucharek said the single-engine plane took off from a small airport near Grand Rapids, Mich., and was at an altitude of about 23,000 feet and descending slowly.
He said the plane was heading south-southeast and had been speeding up and slowing down to dangerous speeds.
Law enforcement was on the scene.
FOX News' Justin Fishel and The Associated Press contributed to this report.