On January 29, American Airlines Flight 5342 collided with a U.S. Army helicopter near Washington’s Ronald Reagan National Airport, killing 67 people, in the deadliest U.S. air disaster in recent history. That alone would have been a crisis for the Federal Aviation Administration, the agency charged with ensuring the safety of air passengers.But the next day, President Donald Trump deepened the FAA’s problems by blaming the disaster on diversity programs, a pronouncement that baffled many in the...