An airspace cluttered with passenger planes and military aircraft. A history of near-crashes. And a growing shortage of air traffic controllers available to manage it all. Some experts, politicians and airport managers have been warning for years of the risks posed by the crowded airspace and volume of flights at Ronald Reagan Washington National Airport (DCA).

President Donald Trump addressed the collision between an American Airlines flight and an Army Black Hawk Helicopter near Reagan National Airport outside of Washington, D.C., late Wednesday.