Police boats combed the banks of the Potomac River on Friday, slowly scanning the shoreline under rainy skies as investigators sought clues into the midair collision that killed 67 people.

Downstream from the Ronald Reagan National Airport debris was picked from the Potomac River after a deadly collision between an American Airlines jet and Blackhawk helicopter.

Rep. Troy Nehls told The Post that Federal Aviation Administration officials had known about the “staffing issues” and that ...