DALLAS (TIP): Stormy weather in Texas has snarled flights at Dallas/Fort Worth, creating headaches for travelers flying to, from or through that busy U.S. airport on Friday.

More than 420 flights – about 180 departures and 240 arrivals – had been canceled there as of 3:50 p.m. ET, according to flight-tracking service FlightAware. That represented about 20% of the airport’s entire daily schedule. And another 600 of Friday’s flights had been delayed. Together that represents about half of the day’s flights at DFW, according to the FlightAware data.

DFW, of course, is the biggest hub for American Airlines, now the world’s biggest airline following its merger with US Airways.

Flight delays also were being reported at Dallas Love Field, the smaller of the two Dallas-area airports. Southwest operates a major base from Love Field.