image copyrightReutersimage captionSouthwest Airlines is among those experiencing website difficulties

Several airline websites in the US and Australia suffered an outage early on Thursday, according to the tracking site Downdetector.

Those affected include the US carriers American Airlines, Southwest Airlines, United Airlines and Delta Air Lines, and Virgin Australia.

Issues were also reported with the sites of several Australian banks, including ANZ, Westpac, St George, and the Commonwealth Bank.

It's unclear if the outages are linked.

"We understand that some of our customers are currently experiencing issues accessing our services," Commonwealth Bank told AFP. "This issue is affecting multiple organisations, including many of the major banks."

Virgin Australia tweeted that its website and guest contact centre were affected.

It comes a day after Southwest Airlines cancelled almost 300 flights and delayed 562 over a computer issue.