Delta Air Lines Inc (NYSE:DAL) has lashed out at CrowdStrike Holdings Inc (NASDAQ:CRWD), claiming last month’s global outage caused it to lose at least US$500 million (£392 million).
Accusing the cybersecurity firm of “negligence” in a letter, Delta said it had racked up losses after being forced to cancel thousands of flights.
“Our customers and employees deserve better,” the airline’s chief executive, Ed Bastian, wrote in a US Securities and Exchange filing.
He added the network failure, which led to the airline cancelling around 7,000 flights over five days from July 19, was “unacceptable”.
It comes as the two companies continue to trade blows following the outage, which affected companies globally, disabling an estimated 8.5 million Windows devices.
CrowdStrike has previously denied full responsibility for Delta’s issues, arguing its flight disruption continued after rival carriers came back online.
The company said it will “aggressively” defend itself against Delta’s claims, which have also stretched to Microsoft Corp (NASDAQ:MSFT).
Delta has been left facing a class action lawsuit from passengers who saw their flights cancelled after the outage, while CrowdStrike’s own shareholders have launched legal action against the cybersecurity firm.