Transportation Secretary Sean Duffy unveiled a sweeping plan to replace decades-old infrastructure to boost safety, cut delays, and support future air travel in a move to modernize the United States’s air traffic control system.

Duffy urged lawmakers to secure tens of billions of dollars in funding to revamp the nation’s overburdened air traffic system, citing outdated equipment, severe personnel shortages, and deteriorating infrastructure. He estimated the overhaul could take between three and four years.