Plane Flies Too Close to Air Force One Near Palm Beach

— -- An aircraft in Florida flew closer than it should have to Air Force One on Friday, sources told ABC News.

The plane, which sources say was flying parallel to Air Force One as it approached Palm Beach, should have maintained a separation of at least three nautical miles from President Trump’s plane, which was en route to his Mar-a-Lago estate for the weekend.

According to one source, the two aircraft made visual contact with one another. Another source with knowledge of the incident said the two planes were flying parallel and that both were in constant contact with air traffic control and never at risk of a collision.

The president's plane, a Boeing 747, is considered the "flying White House" and airspace around it, while the president is on board, is carefully monitored.

Officials are investigating the reasons behind the "loss of separation" incident, which will likely include interviews of pilots and controllers.