Fourth of July Travel: What to Expect This Weekend

By midafternoon on Wednesday, United, which maintains a hub at Newark Liberty International Airport, had canceled about 15 percent of the nationwide flights it had planned for the day, according to FlightAware. Endeavor had canceled about 12 percent of its flights, while JetBlue had canceled about 9 percent and Republic canceled about 8 percent.

United and JetBlue attributed to the problems to the weather, but also to the F.A.A.

In a statement Wednesday, United said air traffic staffing shortfalls over the weekend had contributed to “a tough operating environment.” This blame echoes what United’s chief executive, Scott Kirby, told employees in a memo earlier this week, saying that “the F.A.A. frankly failed us this weekend.” JetBlue said in a statement that it had struggled to keep up with its flight schedule after air traffic control limited trips for all airlines into and out of New York airports.

The F.A.A. said it had no air traffic control staffing issues along the East Coast on Monday or Tuesday. In a statement, the agency said that it “will always collaborate with anyone seriously willing to join us to solve a problem.”

Yet air traffic control has long been short-staffed, and controllers at many facilities often work six-day weeks to cover for those shortcomings.

In a report published last week, the Transportation Department found that most of the 26 critical air traffic control facilities it identified were understaffed by 15 percent or more, as of March 2022. One of those facilities, New York Terminal Radar Approach Control, which oversees some of the nation’s most complex and challenging air space, employed only 54 percent of its target number of controllers.

The report stated that the problem had been years in the making, something that United’s Mr. Kirby noted on Monday, too.

“It’s not the fault of the current F.A.A. leadership that they are in this seriously understaffed position — it’s been building up for a long time before they were in charge,” he said in his staff memo.