Southwest Airlines is suing the city of San Antonio. The Dallas-based carrier filed a federal lawsuit on Thursday that also names San Antonio Director of Airports Jesus Saenz as a defendant. The lawsuit claims the city used subjective factors when assigning airlines at San Antonio International Airport's terminals. City Manager Erik Walsh and Mayor Ron Nirenberg met with Southwest executives on Tuesday. The airline threatened to sue if the city didn't delay the October 1st deadline for executing the new airport leasing agreement.