The George Bush Intercontinental Airport in Houston, Texas, is one of the airports affected by the Federal Aviation Administration's recent decision to reduce flight operations.

Airports in New York, Los Angeles and Chicago along with hubs across the U.S. are among the 40 that will see flights cut starting Friday due to the government shutdown, according to a list distributed to the airlines and obtained by The Associated Press.

The Federal Aviation Administration said Wednesday that it will reduce air traffic by 10% across 40 “high-volume” markets to maintain travel safety as air traffic controllers exhibit signs of strain during the ongoing government shutdown.

The airports impacted cover the busiest across the U.S. — including Atlanta, Denver, Dallas, Orlando, Miami, and San Francisco. In some of the biggest cities — such as New York, Houston and Chicago — multiple airports will be affected.

The FAA is imposing the flight reductions to relieve pressure on air traffic controllers who are working without pay during the government shutdown. The agency has already been delaying flights at times when airports or other FAA facilities are short on controllers.

More air traffic controllers have been calling out of work as the shutdown drags on and the financial pressure on them mounts.

Controllers already missed one paycheck, and they are scheduled to again receive nothing on next Tuesday’s payday.

Airlines said they would try to minimize the impact on travelers. United Airlines said it would focus the cuts on smaller regional routes that use smaller planes like 737s.

Passengers should start to be notified about cancellations Thursday.

The AAA recommended that travelers download their airline’s app and turn on notifications. United Airlines and Delta Air Lines both said they will offer refunds to passengers who opt not to fly -- even if they purchased tickets that aren’t normally refundable.