On the first day of reductions across the nation’s airspace, Denver International Airport is experiencing a wave of flight cancellations.

There are 74 cancelled flights at DIA as of Friday morning, according to air travel disruption tracker FlightAware.

The top cancelled airlines are SkyWest, Southwest, United and Frontier, FlightAware shows.

Major airlines are asking travelers to check their flights before arriving to the airport and offering options to rebook or cancel.

The Federal Aviation Administration announced Wednesday it would reduce air traffic by 10% across 40 “high-volume” airports in the U.S. as air traffic controllers shortages have exacerbated because of the government shutdown and federal workers are working without pay.

Denver International Airport is the third-busiest airport in the U.S. and was on the FAA’s list of 40 airports.

The FAA said reductions will start at 4% on Friday and ramp up to 10% by Nov. 14, according to its official order published Thursday evening. It will be in effect from 6 a.m. to 10 p.m. local time and impact all commercial airlines.

Denver’s airport officials asked the FAA if it could use airport revenue to pay the salaries of its air traffic controllers during the shutdown. The airport officials also said they would request reimbursement from the federal government for those wages once the shutdown is resolved.

“This is a critical time for travel both here at DEN and around the country,” Phil Washington, the airport’s chief, said in a Wednesday statement. “Staffing issues are already being identified at a number of airports, impacting travel. As the shutdown drags on, air traffic controllers, in particular, are being stressed unnecessarily.”

Reporters Deborah Grigsby and Michael Braithwaite contributed to this report.