WASHINGTON — Major air safety failures and last-minute mistakes caused Thursday night’s midair collision over the Potomac River that left 67 people dead, according to expert observers and officials.

The Black Hawk pilots who collided with an American Airlines plane last month may not have heard vital information given by air traffic control to fly behind the passenger jet seconds before the crash ...

An engine flameout problem that occurred on two separate Air Force-owned Global Hawks over the summer has contributed to a delay with the Navy's Global Hawk Maritime Demonstration program, according ...