The transportation secretary’s decision came after the National Transportation Safety Board cited a long history of near collisions between helicopters and airplanes near the nation’s capital.

There's an "intolerable risk to aviation safety" with helicopters and planes flying too close to each other near DCA.

Federal investigators looking for the cause of the January collision between a passenger jet and an Army helicopter near Washington, D.C., that killed 67 people are recommending a ban on some helicopter flights.