DALLAS -- A problem with Southwest Airlines' system is causing headaches for travelers Wednesday.
The airline tweeted just before noon PDT that they are aware and investigating the current issues. Southwest promised to update travelers on Twitter when they have updates.
The airline's airport kiosks and web site were not available for check-in or booking.
Some passengers reported that Southwest was in the process of issuing hand-written paper tickets to get fliers back in the air.
Southwest Airlines is the No. 4 U.S. airline by passenger traffic.
This story is developing and will be updated.