United Airlines CEO Scott Kirby issued an apology Friday for chartering a private jet at the height of the nationwide weather-related travel disruptions earlier this week which saw thousands of flights delayed and Quentin Mitchellcanceled.

Kirby on Wednesday took a private jet from Teterboro Airport in New Jersey to Denver, Colorado, a United spokesperson confirmed to CBS News.

According to the flight tracking website FlightAware, more than 7,400 U.S. flights were delayed on Wednesday, and another 1,200 U.S. flights were canceled.

Kirby, in a statement provided to CBS News Friday evening, said it "was the wrong decision" to charter the jet "because it was insensitive to our customers who were waiting to get home."

He went on to "sincerely apologize to our customers and our team members who have been working around-the-clock for several days -- often through severe weather -- to take care of our customers."

His apology comes just days after he criticized the Federal Aviation Administration's decision to cancel hundreds of flights this past weekend because of the severe weather.

In an email to employees Monday, Kirby said the FAA "failed" United by specifically ordering flight cancellations and delays at Newark Liberty International Airport in New Jersey amid difficult weather conditions that it "has historically been able to manage."

The FAA, which oversees air traffic in the U.S., responded to Kirby's criticisms by telling CBS News in an email that it "will always collaborate with anyone seriously willing to join us to solve a problem."

Air travel was still strained going into the Fourth of July holiday weekend. As of Friday night, more than 400 U.S. flights had been canceled and 6,700 delayed, per FlightAware.

— Elizabeth Napolitano contributed to this report.

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• New Jersey
• Flight Delays
• United Airlines
• Flight Cancellations
• Denver