Delta cancels another 600 flights in wake of cyber outage

Delta Air Lines cancelled more than 600 flights on Monday, as the US air carrier continued to struggle to restore operations after last week's global cyber outage, even as other airlines were recovering from the incident.

About 16 per cent of Delta's flights had been canceled as of 7am EST, according to data from FlightAware, out of roughly 1,100 flights to or from the United States overall, the web site said.

The issue has stranded thousands of Delta travellers across the United States, with some having to rent cars to drive hundreds of miles while others could have to wait days for new flights or cancel trips altogether.

The Atlanta-based airline is battling operational issues after the outage hit its crew tracking system. Delta's total number of cancelled flights since Friday has exceeded 5,000.

A Delta spokesperson did not immediately respond to an emailed request for comment.

A software update by global cybersecurity firm CrowdStrike triggered system problems for Microsoft customers, including many airlines, on Friday.

Although other US airlines have largely recovered, Delta has struggled to return to normal. American Airlines had called off one per cent of its flights on Monday, while United Airlines cancelled less than one per cent.

CrowdStrike said a significant number of the 8.5 million affected Microsoft devices were back online.