Ed Bastian, CEO of Delta Air Lines, speaks during a keynote at CES 2020 in Las Vegas on Jan. 7, 2020.

Delta Air Lines CEO Ed Bastian on Friday offered employees two free travel passes to thank staff members who were caught in massive disruptions last month sparked by a botched CrowdStrike software update that stranded thousands of customers and crew.

Delta had more trouble than competitors in recovering from the outages that took thousands of Windows machines offline around the world, affecting industries from health care to banking.

The carrier canceled more than 5,000 flights between July 19 and July 24, more than it did in all of 2019, according to FlightAware. Bastian said earlier this week that the incident cost the company about $500 million, a sum that is equal to about 40% of Delta's second-quarter profit. A crew-tracking platform was a contributor to the cancellations and disruptions, the airline has said.

Delta told CNBC's "Squawk Box" on Wednesday that the airline had to manually reset 40,000 servers.

The disruption "has been a humbling moment for our company," Bastian said in his note on Friday, which was seen by CNBC. "I know it's been extremely difficult, and I'm deeply sorry for what you have endured. An operational disruption of this length and magnitude is simply unacceptable — you and our customers deserve better."

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