After a brief evacuation Wednesday, people were allowed back into the Capitol and Supreme Court (search) in Washington.

The buildings were cleared after a private aircraft, 13 miles southwest of Reagan National Airport and heading eastward, had flown into the restricted airspace, said Greg Martin, a spokesman for the Federal Aviation Administration (search).

The Department of Homeland Security confirmed to Fox News that it was Kentucky Gov. Ernie Fletcher's plane that violated the air space.

The incident sent hundreds of people out of the building where the body of former President Ronald Reagan will lie in state.

Masses of people who had lined up in front of the Capitol to pay last respects were told to "run," one man waiting in line told Fox News.

The plane carrying Reagan's body had not yet arrived in the Washington area from California when the evacuation took place.

The Associated Press contributed to this report.