Trump suggested without evidence that the deadly midair collision of two aircraft in Washington was the result of the Federal Aviation Administration's efforts to hire a more diverse and equitable workforce.

Trump levelled the accusation on Thursday at a White House press conference called to update Americans on the Wednesday night crash in which a passenger jet about to land at Reagan National Airport collided with an Army helicopter on a training flight.

It drew swift criticism from aviation safety experts, disability rights advocates and Democratic lawmakers.

There were no survivors among the 64 people on the jet and three soldiers on the helicopter.

The cause of the air crash is unclear, and there is no evidence that efforts to make the federal workforce more diverse have compromised air safety. Yet Trump used the briefing to step up his rhetoric on the issue, in this case against the FAA, which regulates commercial U.S. air travel.

"The FAA diversity push includes focus on hiring people with severe intellectual and psychiatric disabilities. That is amazing," Trump said, claiming the FAA wanted people "with severe disabilities, the most under-represented segment of the workforce, and they want them in and they want them - they can be air traffic controllers".

Asked how he could blame diversity, equity and inclusion hiring for the crash, Trump said, "Because I have common sense".

"We want brilliant people doing this," he said.

With AAP.