The websites of American Airlines, Southwest Airlines, United Airlines and Delta Air Lines faced an outage on early Thursday.
According to the monitoring website Downdetector, thousands of user reports indicated problems with the Southwest Airlines website, while over 400 reports indicated problems with the Delta Air Lines website.
According to the 9News, customers of several Australian banks including Westpac, St George, ANZ and the Commonwealth Bank reported that they were unable to log in to the mobile apps and websites.
"We understand that some of our customers are currently experiencing issues accessing our services," the Commonwealth Bank said, as quoted by AFP. "This issue is affecting multiple organisations, including many of the major banks."
Virgin Australia said that it was experiencing a system outage.
Earlier, Southwest Airlines cancelled almost 300 flights and delayed over 500, a day after temporarily halting operations due to a computer glitch.