U.S. airlines began canceling hundreds of flights on November 6 due to the Federal Aviation Administration's (FAA) order to reduce traffic at the country's busiest airports starting on November 7 because of the government shutdown.

More than 790 planned November 7 flights were cut from airline schedules, according to FlightAware, a website that tracks flight disruptions. That number, already four times higher than November 6’s daily total, was likely to keep climbing.

The 40 airports selected by the FAA spanned more than two dozen states and included hubs such as Atlanta, Dallas, Denver, Los Angeles, and Charlotte, North Carolina, according to the agency's order. In some metropolitan areas, including New York, Houston, Chicago, and Washington, multiple airports were impacted.

The FAA said in the order that the reductions were to begin on November 7 at 4% and ramp up to 10% by November 14. They were in effect between 6 a.m. and 10 p.m. local time and impacted all commercial airlines.

The decision to reduce service at high-volume markets was meant to maintain travel safety as air traffic controllers exhibited signs of strain during the shutdown. It also came as the Trump administration continued to ramp up pressure on Democrats in Congress to end the shutdown.

With continued delays and unpredictable staffing shortages, which are driving fatigue, risk is further increasing, and the FAA is concerned with the system's ability to maintain the current volume of operations, the order read.

Hours before the reductions went into place, airlines were scrambling to figure out where to cut. American Airlines said it reduced its schedule at the listed airports by 4% from November 7 through November 10, about 220 cancellations each day, and planned to move from there toward the 10% target. The carrier said its international schedule was expected to remain untouched.

Passengers with plans for the weekend and beyond waited nervously to see if their flights would take off as scheduled. Some travelers began changing or canceling itineraries preemptively.

This article was provided by The Associated Press.