(CNN) — A shortage of air traffic controllers has major airlines considering summer schedule cuts to prevent delays. American Airlines told CNN it plans to slash service at two major New York area airports, and both United Airlines and Delta Air Lines have asked the Federal Aviation Administration for permission to trim up to 10% of flights in the busy region. Last month, the FAA gave airlines an opening to scale back service at the three major New York City area airports -- John F. Kennedy, LaGuardia and Newark -- warning air traffic control "staffing shortfalls" at New York Terminal Radar Approach Control could amplify delays by 45%. That New York facility is operating at about half of its target staffing level. Nationwide, two in 10 air traffic controller positions are unfilled. The union representing air traffic controllers says staffing levels have dropped 10% over the last decade.
American will cut flights on routes between LaGuardia and Dallas-Fort Worth, Miami and Kansas City, as well as flights between Newark and Chicago O'Hare.
"American will temporarily reduce frequencies on select routes from LaGuardia Airport and Newark Liberty International Airport this summer," said airline spokesperson Curtis Blessing in a statement. "We're proactively reaching out to affected customers to offer alternate travel arrangements."
Delta Air Lines says it is "reviewing our network to ensure the best customer experience throughout the summer travel season" and will notify the FAA of any schedule changes before the April 30 deadline.
New York-based JetBlue could be especially hit by traffic problems in the region.
The airline told CNN it is reviewing options "for reducing our flight schedule at JFK and LaGuardia airports to help ease constraints on the system." In a statement, the airline called scaling back service "disappointing," adding that it will "share specific details on our schedule reduction once we have finalized our plan."
Americans flying into or through the Northeast this summer may not see a dramatic drop in capacity. Airlines are currently flying about 10% fewer flights compared to 2019, before the pandemic, according to their industry group Airlines for America.
But the number of available seats is up about 13%, thanks to airlines flying larger aircraft -- known in the industry as "upgauging."
The moves are in an effort to prevent a repeat of last summer's meltdowns that stranded passengers en masse.
One in five flights nationwide was delayed between Memorial Day and Labor Day, according to data from FlightAware. Airlines blamed weather and said the FAA was shorthanded. Federal officials pointed the finger at airlines being slow to rebuild from the pandemic.
The air traffic controller union has said it is working with agency officials on a permanent fix to the understaffing issues. The FAA paused hiring and training of air traffic controllers during the pandemic, but the hiring has since resumed.
Airlines say they've gone on a hiring spree but that the FAA has been slower to rebuild the air traffic controller ranks.
"We are essentially overstaffed right now and they are understaffed," Sharon Pinkerton of Airlines for America recently told Congress. "And, so, I think they need to take that seriously and address it. ... We don't have enough air traffic controllers and we don't have the right technology."
The airline moves come amid increased scrutiny of increased near collisions at airports. Among other steps, the FAA has called for more supervisor oversight in control towers and extra controller training for "unusual circumstances."
The FAA recently published an "aviation safety call to action," urging carriers to "reinforce adherence to published processes and procedures."