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.”

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.

A regional American Airlines jet and a Black Hawk military helicopter collided over Washington, D.C., Wednesday night in the first major commercial airline crash since 2009. Three emergency care providers in the Washington, D.C., region have confirmed with ABC News that they have not yet received any patients from the crash.