WASHINGTON (AP) _ Thumbs up and arms spread in triumph, 11-year-old John Kevin Hill stepped from his single-engine airplane at Washington National Airport on Wednesday after becoming the youngest known pilot to fly across the United States.

''I'm glad to be back on solid ground,'' said the boy, who lives with his parents in Arlington, Texas.

After a delay caused by poor weather, John Kevin took off at 12:37 p.m. EDT from Greater Cincinnati International Airport and touched down in Washington just after 3 p.m., ending his week-long journey from Los Angeles.

''I never let go of the controls. I'd get tired but I'd just stick with it,'' said the youngster. ''Sometimes it was just like a roller coaster.''

A throng of reporters, television cameras and photographers overwhelmed well-wishers who had gathered to greet him.

Moments after giving up his pilot's seat - which was padded with three extra pillows to raise him to window level - John Kevin was greeted by Texas billionaire H. Ross Perot, who happened to be flying out of the private aviation terminal at National Airport.

''I think it's great. My son flew a helicopter around the world,'' Perot said, congratulating the boy. ''I'm just really impressed by it.''

When informed by John Kevin's mother, Patsy, that her son plans to attempt an around-the-world flight when he's a little older, Perot said: ''Tell him I'm glad he's going to give it a few years rest.''

At the airport, John Kevin was presented with a congressional certificate of appreciation and a deck of playing cards from Air Force II by Rep. Dick Armey, R-Texas, along with several other awards.

The youngster's trip began in Los Angeles on June 24 and included stops in Cedar City, Utah; Denver and Cincinnati. He was accompanied by his flight instructor, a newspaper reporter and a National Geographic photographer.

The boy must be accompanied by his instructor, Michael Fields, when he flies because he is too young to obtain a pilot's license. John Kevin is allowed to fly only under visual flight rules, which means the weather must allow for extended visibility.

The newspaper reporter, Michelle Stein of the Fort Worth Star-Telegram, said she was not worried about flying with an 11-year-old pilot in inclement weather conditions.

''I'm not worried. It think that flying with John Kevin is one of the neatest things I've ever done,'' Ms. Stein said. ''When he gets behind the yoke he's not like a kid. He's like an adult.''

Fields said the boy had successfully flown around several storms over the Rocky Mountains, near Denver.

''We've got a storm scope on board, so we can deviate around anything we don't want to get involved with,'' Fields said. ''We go way around them.''

John Kevin said he attempted the transcontinental flight to set a world's record, but he had no assurance of meeting that goal. Officials for the Guinness Book of World Records said no statistics are available for transcontinental flights by youths.

Johnny Hill, Kevin's father, said he hoped the Guinness book would create a new category for his son.

John Kevin's parents have been following the path of the coast-to-coast trip aboard commercial flights.