(Houston, TX) — Southwest Airlines is grappling with maintenance problems that are resulting in a larger number of planes out of commission than usual.

The Dallas-based carrier canceled about 100 flights nationwide on Tuesday.  On any given day, Southwest expects about 20 of its fleet of 750 aircraft to be down for maintenance.  Every day since last week, it’s been more than twice that many.

Southwest says it’s working to reduce customer inconvenience.