President Donald Trump’s own policies have prompted departures of key staff and hurt morale at the aviation agency, complicating multi-billion dollar modernization plans.

The Trump administration has announced a plan to replace the country’s aging air traffic control system with an all-new technology—but needs Congress to allot tens of billions of dollars.

Transportation Secretary Sean Duffy will call for tens of billions of dollars to overhaul America’s air-traffic control system to address crumbling infrastructure, dramatic staffing shortfalls and failing technology.