 Air travel troubles continue following yesterday's IT outage that caused more than 3,000 flights to be canceled. Nearly 1,300 flights today canceled. According to FlightAware.com, more than half of them Delta and United flights. A glitched software update to blame for crashing thousands of Windows-based systems. Microsoft actually says the problem affected 8.1 million Windows devices. That's less than 1% of all Windows machines.