United Airlines Chief Executive Scott Kirby has blamed the Federal Aviation Administration (FAA) after severe storms led to thousands of canceled flights in recent days.

"I'm ... frustrated that the FAA frankly failed us this weekend," he said in a memo to the company's employees on Monday.

"We estimate that over 150,000 customers on United alone were impacted this weekend because of FAA staffing issues and their ability to manage traffic," Kirby said in a memo reviewed by Reuters.

Thunderstorms and failing equipment at an FAA facility created significant delays for air travelers across the U.S. East Coast on Sunday evening as Washington and New York were forced to briefly halt most incoming flights.

Kirby said that the FAA reduced arrival rates by 40% and departure rates by 75% on Saturday. That, he said, led to massive delays, cancellations and "put everyone behind the eight ball when weather actually did hit on Sunday and was further compounded by FAA staffing shortages Sunday evening."

An FAA spokesperson said, "We will always collaborate with anyone seriously willing to join us to solve a problem."

Last weekend, about 26,000 flights by all airlines were delayed and over 4,000 canceled between Saturday and Monday after thunderstorms ripped through parts of the United States, according to data from flight monitoring service FlightAware.

(Reporting by Jaiveer Singh Shekhawat in Bengaluru and David Shepardson in Washington; Editing by Maju Samuel)