As investigators try to uncover what happened when an airplane and a helicopter collided over the Potomac River, here is the latest information.

U.S. authorities said on Thursday it was not yet clear why a regional jet crashed into a U.S. Army helicopter at a Washington airport, killing 67 people in the deadliest U.S. air disaster in more than 20 years.

An American Airlines jet with 60 passengers and four crew members aboard collided Wednesday with an Army helicopter while landing at Ronald Reagan National Airport near Washington, prompting a large search-and-rescue operation in the nearby Potomac River.

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As investigators look into the cause of Wednesday night's plane crash, pilots share their initial take on the collision.

We are learning more about some of the 67 victims aboard the American Eagle plane and Black Hawk helicopter that collided near Washington, D.C.