Nov. 12, 2025, 11:40 AM ESTBy Rebecca CohenFor the second day, the Federal Aviation Administration will continue to enforce its mandate to cancel 6% of flights at 40 high-traffic airports, as the U.S. House of Representatives is set to vote on a Senate-passed bill to end the government shutdown.As of Wednesday morning, 890 flights within the U.S. had been canceled and more than 750 had been delayed, according to flight tracking website FlightAware.United Airlines announced that it had already canceled 300 flights on Wednesday alone. Up to 8% of flights, or approximately 1,600 trips, could be cut on Thursday at the country’s busiest airports, including those in the New York area and in cities including Chicago, Atlanta, Denver, Phoenix, Dallas and L.A.The FAA began reducing flights from major airports by 4% on Friday and has gradually increased that percentage throughout the week. By this coming Friday, the FAA said, the reduction in flights is supposed to reach 10%.Delta CEO Ed Bastian said in an interview on CNBC on Wednesday that the airline cut 2,500 flights last week, which “is going to cost Delta a significant amount.”Transportation Secretary Sean Duffy spoke to reporters from Chicago O’Hare International Airport on Tuesday, warning that more trouble with air traffic could be on the way if the government does not reopen.“If the House does its work tomorrow, we’re well on our way” to getting air travel back to normal, Duffy said Tuesday.He noted, however, that if a bill is not passed quickly, disruptions to flight schedules will likely get worse before one of the busiest travel weeks of the year — Thanksgiving, when 31 million Americans are expected to fly. Some airlines are already talking about “grounding their planes” if the government doesn’t reopen soon, he said.Travelers walk though the terminal Wednesday at O’Hare International Airport in Chicago.Nam Y. Huh / APIt remains unclear how quickly the system can be righted once the government reopens, as flight schedules are typically laid out in advance. The FAA did not respond to a request for comment on this matter sent Tuesday afternoon.The airlines have said they think it could take a few days, once the government reopens and the FAA gives the green light to return to their normal cadence.David Seymour, the chief operating officer of American Airlines, told NBC News that the quick return to normal operations will depend on “working with the FAA to ensure that we maintain the safety of the system.”He added that “with Thanksgiving just around the corner, it’s going to be super important that we’re there, able to deliver to our customers.”Duffy said that aviation safety is at risk, and labor shortages are to blame for the flight cancellations and delays. If there are not enough employees to man the skies, the FAA must adjust the schedule to ensure planes in flight reach their destinations safely.But staffing at air traffic control towers improved on Tuesday — even though these essential government employees have now been working without pay for more than a month. These controllers will receive back pay when the shutdown ends and are expected to get about 70% of their missed pay within 48 hours of the government reopening, with the remaining 30% coming within that week.Still, travelers are increasingly frustrated that their plans are being thwarted.“I don’t trust any airports. I don’t trust any of this stuff anymore. I have totally lost faith,” one traveler told NBC News.Some airlines, like United, are doing what they can to alleviate customer stress.In a letter to the company, United CEO Scott Kirby wrote that the airline has given “our customers as much notice and flexibility as possible knowing the circumstances were ever-changing,” like publishing the list of cancellations on a dedicated website, using the app to alert customers of alternative flights to get them to their destinations and offering refunds to all customers — even if their flights had not been canceled.Also complicating matters is inclement weather this week.Freezing temperatures across two-thirds of the country and lake-effect snow are to blame for a cold, messy start to the week, and a heavy storm will bring rain and wind to the West Coast starting Wednesday. It is not clear how many of the flight cancellations and delays are the result of weather instead of the FAA mandate.Rebecca CohenRebecca Cohen is a breaking news reporter for NBC News Digital.Tom Costello and Kathryn Prociv contributed.