On March 14, Boeing discovered that "Yankee White" credentials for about 250 employees who work on the Air Force One planes had lapsed, the Air Force and Boeing confirmed.
All of the workers involved have retained current top secret clearances, according to the Air Force and Boeing.
However, the additional Yankee White clearance is required for individuals working on matters connected to the presidential aircraft.
"When Boeing discovered this administrative issue, we quickly notified the Air Force, and, in coordination with the Air Force, we temporarily suspended access to the VC-25A and VC-25B areas for those Boeing employees who were affected," a Boeing spokesperson said.
On March 19, "the vast majority of employees" with lapsed Yankee White credentials were approved to begin working in the secured areas where Air Force One planes are built and maintained, the Air Force said.