FAA Warns of Air Traffic Cuts Friday if Government Shutdown Continues

The Trump administration announced on Wednesday that it would cut 10 percent of air traffic at 40 of the nation’s busiest airports, in a move that analysts said would force airlines to cancel thousands of flights while the administration tries to push Democrats to end the government shutdown.

Transportation Secretary Sean Duffy said the reductions were an attempt to “alleviate the pressure” on air traffic controllers, who have been working without compensation since the start of the shutdown and have not received a paycheck since mid-October. He said the administration would announce the affected markets on Thursday, as the year’s busiest travel season approaches.

The cuts would start taking effect on Friday, potentially forcing hundreds of thousands of travelers to change plans on short notice, as airlines are pressured to slash capacity across their routes. Representatives of several major airlines and Airlines for America, a trade association, said they were working with the Federal Aviation Administration to understand the details of the new requirements, but had yet to make changes.

Turmoil in the nation’s air travel system, which moves millions of passengers daily, has long been considered to be among the most tangible and disruptive potential effects of government shutdowns — and consequently, one of the biggest pain points to force a deal. Despite a shutdown that stretched into a record 36th day on Wednesday, the system has largely held up so far, though it has shown some worrisome signs of fraying.

Mr. Duffy has been sounding an alarm about the pressures on the Federal Aviation Administration’s force of certified air traffic controllers, most of whom were already working overtime shifts to compensate for about 3,000 vacancies among its 14,000 positions before the shutdown. Controllers, who are required to work through the shutdown without salary, are facing their second missed paycheck on Tuesday.

Mr. Duffy warned earlier this week of “mass chaos” if the shutdown went on, and said the F.A.A. could close parts of the national airspace to traffic to avoid a broader meltdown. His Wednesday announcement marked a step in that direction, as he and Bryan Bedford, the F.A.A. administrator, forecast more restrictions if staffing worsened.