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Southwest Airlines Co. plans are on the asphalt at San Francisco International Airport (SFO) in San Francisco, California, USA, Friday 19th. January 2018. Southwest Airlines Co. is scheduled to release earnings in January 25. Photographer: David Paul Morris / Bloomberg via Getty Images
Southwest Airlines told its mechanic on Friday that it is experiencing an "operational emergency" due to an unusually high number of grounded jets – and demanded that they appear for work or risk termination, according to a company memo issued Friday and seen by CNBC.