WASHINGTON -- A small plane strayed within three miles of the White House Wednesday, forcing an evacuation of government buildings so quick that Capitol police, rushing to get House Minority Leader Nancy Pelosi to a secure location, lifted her out of her shoes.

The stocking-feet Pelosi, other House and Senate leaders and Vice President Dick Cheney were spirited away and thousands of others evacuated from the White House and the Capitol after the plane entered restricted airspace over Washington, sending the capital into a temporary frenzy of emergency activity.

President Bush, biking with a high school friend at a Maryland nature reserve, was unaware of the 15-minute scare that set the government on edge. He learned the details when he returned to the White House.

Shouts of "For your safety, exit the building!" and "This is not a drill!" touched off an organized but hurried rush out of the Capitol. At the White House, people were either urged to leave the building or head to the basement.

Within minutes, the words were "all clear." Warplanes scrambled from Andrews Air Force Base had fired four flares when they got no response from the pilot. Only then did the plane veer west and the jet fighters escorted it to an airport in Frederick, Md.

A pilot and student pilot, flying from Pennsylvania to an air show in North Carolina, were taken into custody. The government decided not to press charges after interviewing the men and determining that the incident was an accident. "They were navigating by sight and were lost," said Justice Department spokesman Kevin Madden.

Officials had been concerned because the plane appeared to be "on a straight-in shot toward the center of the Washington area," said Capitol police chief Terrance W. Gainer.

The White House raised its threat level to red -- the highest -- for eight minutes, said spokesman Scott McClellan. First lady Laura Bush and former first lady Nancy Reagan, overnighting at the White House for a special event, were moved to secure locations.

At the Capitol, lawmakers, tourists and reporters raced out of the building, dodging the speeding motorcades of Latin American leaders who had been meeting with members of Congress.

At the Supreme Court, guards told some people to leave the building while others were shepherded into the underground parking garage, where Justices John Paul Stevens, Sandra Day O'Connor and Stephen Breyer were seen chatting. At Treasury, an announcement on the loudspeaker advised employees to move to a shelter.

The Justice, Defense and State departments were exceptions, with none evacuated. Defense Secretary Donald H. Rumsfeld remained at the Pentagon, where many were killed when terrorists crashed an airliner on Sept. 11, 2001. Pentagon officials decided the two-seater plane was too small to do serious damage to the five-sided building. Secretary of State Condoleezza Rice conducted a television interview unaware of the plane.

The incident began in Washington at 11:28 a.m., when Federal Aviation Administration radar picked up the aircraft, a small Cessna 152 with high wings. Gainer said the first alert went out when the plane was 21 miles -- 17 minutes -- from the city.

Two Black Hawk helicopters were dispatched at 11:55 a.m. from Reagan National Airport. Two F-16 jet fighters fired four warning flares when the Cessna's pilot did not respond to radio calls.

"If he wouldn't have responded, intentionally or not, he could have been shot down," said Master Sgt. John Tomassi of the North American Aerospace Defense Command in Colorado Springs, Colo.

The plane was registered to Vintage Aero Club, a group of people who fly from Smoketown Airport in Pennsylvania's Lancaster County, said club member Merv King. Former club member John E. Henderson said the plane was to be flown by Jim Sheaffer of Lititz, Pa., and student pilot Troy Martin, of Akron, Pa., to an air show in Lumberton, N.C.

Martin's wife, Jill, said, "Troy was discussing with me last night after they made their flight plans all about the no-fly zones and how they were going to avoid them. He said they were going to fly between two different restricted areas."

Washington's Reagan National Airport has been closed to general aviation, the non-airline planes, since the Sept. 11 terrorist attacks. In the 3 1/2 years since then, hundreds of small planes have flown within the restricted airspace around the capital -- a 15 3/4-mile radius around the Washington Monument.

However, it's rare for fighter jets to be scrambled in response.