Within minutes after the sounding of the all-clear and the return of thousands of people evacuated from the White House, the Capitol, the Supreme Court and other government buildings, some members of Congress called for quick action to determine if Washington is safe from terrorism by air.

The incident lasted less than half an hour, but the effect could linger as authorities assess their response.

"There still are a lot of problems with these evacuations," said Sen. Dianne Feinstein, D-Calif. "It seems every time we have one we learn something from them."

Although some in Congress and elsewhere described Wednesday's events as an overreaction to what turned out to be an innocent intrusion, others called for tighter rules that might include expansion of the 16-mile no-fly zone around the Washington Monument that has been in effect since the terrorist attacks of Sept. 11, 2001.

Rep. Dan Lungren, R-Gold River, who fled from the third floor of the Capitol when the alarm sounded, predicted that several committees would explore the incident.

Rep. Howard Coble, R-N.C., chairman of the House subcommittee on homeland security, praised the decision to withhold fire at the offending aircraft and to escort it instead to a landing strip in Frederick, Md., about 40 miles from the White House.

As soon as the Cessna 150 aircraft reached the ground, police seized the occupants, an experienced flight instructor and a student pilot.

FBI and Secret Service agents questioned the men, and in late afternoon released them without immediately filing criminal charges. Authorities said the flight instructor faced the loss of his license, the student his chance to get one, and both could be fined.

The men were identified as student pilot Troy Martin, 36, of Akron, Ohio, and his teacher, Hayden Sheaffer of Lititz, Pa. Sheaffer is in his 70s.

The men were flying from Pennsylvania to an air show in North Carolina.

The incident began at 11:28 a.m., when Federal Aviation Administration radar picked up the aircraft, a small two-seater Cessna. Capitol Police Chief Terrance Gainer said the first alert went out when the plane was 21 miles - 17 minutes - from the city.

One Black Hawk helicopter and one Citation jet were dispatched at 11:47 a.m. from Reagan Washington National Airport. Two F-16 jet fighters, scrambled from Andrews Air Force Base, 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 Cessna then turned to the west and the warplanes escorted it to the airport in Maryland.

Sheaffer confirmed he had been released by authorities but declined to comment further when reached on his cell phone by the Associated Press.

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."

In Washington, the only apparent injuries were a few twisted ankles from running down stairs and bruised feet from dashing without shoes across sidewalks and lawns away from federal buildings as police shouted "Run, run, run" and "This is no joke."

As thousands of people heeded the warning, a fighter jet roared overhead and police emergency vehicles screeched through the streets. Mounted police galloped through the crowds on their horses. Sirens wailed as key congressional leaders were whisked away in armored SUVs. Others fended for themselves.

"The urgency and intensity of their voices showed they weren't joking," said Sen. Debbie Stabenow, D-Mich., who left without her purse or cell phone.

"This has the feel emotionally of Sept. 11," said Rep. Christopher Shays, R.-Conn., as he left the Capitol. "The urgency far exceeded anything that has happened before."

Within hours, life seemed back to normal in Congress and at the White House.

White House spokesman Scott McClellan and congressional leaders praised authorities, saying the quick response went according to a careful and tested plan.

President Bush was not among those evacuated when the "red code" was signaled. He was taking a break from the Oval Office by riding a bicycle in a suburban Maryland park, and he returned to the White House shortly after the violating aircraft reached the ground.

But Vice President Dick Cheney, first lady Laura Bush and visiting former first lady Nancy Reagan were among those sped to safety as security forces brought out heavy weapons, creating a grim scene on the White House lawn that replayed on U.S. cable networks and television worldwide.

Since 9/11, hundreds of small planes have flown within the restricted airspace around the capital. But Wednesday marked only the second time since then that an unidentified plane triggered a major evacuation in Washington. Last June, the Capitol and Supreme Court were evacuated shortly before the funeral ceremony for former President Reagan. The approaching plane turned out to be that of Kentucky Gov. Ernie Fletcher, who was coming to Washington for the funeral.

About the writer:

• The Bee's Lawrence M. O'Rourke can be reached at (202) 383-0012 or lorourke@mcclatchydc.com. Margaret Talev of The Bee Washington Bureau, the Associated Press, Chicago Tribune and Knight Ridder Newspapers contributed to this report.