KEY POINTS
  • Southwest Airlines' fourth-quarter profit tumbled more than 21% after the grounding of the Boeing 737 Max drove up the carrier's costs, it said Thursday.
  • Southwest has the most Boeing 737 Max planes in its fleet and on order than any other U.S. airline.
Ground operations employees load baggage onto a Southwest Airlines Boeing 737 aircraft on the tarmac at John Wayne Airport in Santa Ana, California.

Southwest Airlines' fourth-quarter profit tumbled more than 21% after the grounding of the Boeing 737 Max drove up the Dallas-based carrier's costs, it said Thursday.

Southwest has the most Boeing 737 Max planes in its fleet and on order than any other U.S. airline. The planes have been grounded since March after two fatal crashes — one in Indonesia in October 2018 and another in Ethiopia less than five months later — killed 346 people.