Fighter jets were scrambled with two F-16s escorting Flight 990 as it dumped fuel to lessen its weight in order to land on Sunday night.
The Boeing 767, from Washington's Dulles Airport bound for Accra in Ghana, had 144 people on board when the fight broke out, a Federal Aviation Administration spokesman said.
Government officials confirmed that fighter jets were scrambled from Andrews Air Force Base in Maryland.
United spokesman Mike Trevino said Tuesday that the Boeing 767 dumped fuel as a safety precaution to lighten its weight on landing.
The Washington Post, which first reported the incident, reported that the fight began not long after takeoff when a passenger lowered his seat and a passenger behind him objected.
The overnight flight departed at 10.44pm, the newspaper reported.
Not long after that one passenger lowered his seat - presumably intending to attempt to doze off for the 5,000-mile flight.
But it seems he may have reclined a bit too far, inciting the fury of the passenger behind him, who, it appears, was unwilling to have the first passenger's head in his lap for nearly 11 hours.
The second passenger smacked the first passenger, and a fistfight quickly ensued, sources told the Post.
A flight attendant and another passenger intervened, and the pilot - who has full authority over a flight once it is in the air - decided to turn the plane around. Read More