Wednesday night’s fatal crash at Ronald Reagan Washington National Airport involving a commercial airplane and a Black Hawk military helicopter has drawn renewed attention to air traffic controllers and what role they may have played in the accident that is believed to have killed 67 people.

Amid increased concerns about aviation safety, here's how many air traffic controllers there are in the U.S., and how the hiring process works.

One widely shared claim was that Trump fired 3,000 air traffic controllers shortly after taking office for his second term. One post alone (archived) making this claim had received more than 2.7 million views and 25,