Ultimately controllers at Andrews feared the cargo jet would not clear the runway in time, said the officials, who spoke on condition of anonymity because they are not authorized to speak for their agencies.

FAA officials confirmed that the first lady was aboard the plane, but had no additional comment immediately. They expected to release a statement later Tuesday. The first lady's office also had no immediate comment.

The Federal Aviation Administration, already dealing with a series of controversies involving controllers sleeping and watching a movie on the job, on Tuesday sent a team of investigators to the Warrenton radar control center where the mistake was made.