Southwest Airlines is expanding its footprint in Chicago. The Dallas-based airline announced yesterday that they are adding new service from O’Hare Airport, alongside existing service from the carrier’s longtime Chicago home, Midway Airport. Midway remains one of the busiest airports in Southwest’s network. Since first arriving in Chicago in 1985, Southwest has grown into one of the city’s largest employers, with more than 48-hundred Chicago-based employees. The airline is also adding service at George Bush Intercontinental Airport in Houston.