If changes aren't made, that near-miss becomes a mid-air collision,” one aviation safety expert said. “Unfortunately, that's what we had last night.”

Political leaders had warned about the dangers of Ronald Reagan Washington National Airport in Washington, D.C. months before an American Airlines flight collided with a U.S. Army Black Hawk helicopter on its approach to the airport.

An American Airlines plane carrying 60 passengers and four crew members collided with an Army Black Hawk helicopter outside Reagan National Airport near Washington, D.C. Wednesday evening. Three soldiers were onboard the helicopter and a massive search and rescue operation is now unfolding in the Potomac River.