The Trump administration is planning to modernize the aging US air traffic-control system after vulnerabilities with the existing system pushed United Airlines to cut flights at Newark airport.

The FAA did not agree to a recorded interview for this story, but in a written statement it said that growing the controller workforce is “a top priority for the FAA.” It also highlighted that more than 8,300 people recently qualified to take an aptitude test, which is an early step in the process of becoming a controller.