The plane had been cleared to land on Reagan National Airport’s main runway. But in the final moments of the flight, air traffic control asked the pilot to land on a separate, intersecting runway.

President Donald Trump on Thursday slammed his predecessors and Democratic diversity measures and suggested that the Federal Aviation Administration’s diversity efforts had made air travel less safe.

Air traffic controllers at Reagan National Airport exchanged messages with the U.S. Army soldier piloting the Sikorsky UH-60 ...