answers: ATA Airlines
context: History of Southwest Airlines Since its inception in 1967 and its early years when it was prevented from operating, Southwest Airlines has grown to be one of the largest airlines in the United States. Southwest Airlines began with the March 15, 1967, incorporation of "Air Southwest Co." by Rollin King and Herb Kelleher to fly within the state of Texas. Kelleher asserted that by staying within Texas, price controls and market regulations imposed by the federal Civil Aeronautics Board would not apply, and the airline could undercut competitors' prices. Three airlines (Braniff, Trans-Texas Airways and Continental Airlines) started legal action </s> to Dallas. The engine exploded on the Boeing 737-700 and sent shrapnel flying back towards the passenger window.This death was the first in-flight fatality due to an accident in the history of Southwest History of Southwest Airlines Since its inception in 1967 and its early years when it was prevented from operating, Southwest Airlines has grown to be one of the largest airlines in the United States. Southwest Airlines began with the March 15, 1967, incorporation of "Air Southwest Co." by Rollin King and Herb Kelleher to fly within the state of Texas. Kelleher asserted that by staying within Texas, </s> airline at Love Field, maintains its headquarters, hangars, training centers and flight simulators adjacent thereto and reflects its ties to Love Field in its winged heart livery and its stock exchange ticker symbol (LUV). In 2008, Southwest contracted with Pratt and Whitney to supply the proprietary Ecopower water pressure-washing system, which allows Southwest to clean grime and contaminants off engine turbine blades while the aircraft is parked at the gate. Frequent use of the Ecopower system is estimated to improve fuel efficiency by about 1.9%. Southwest paid US$7.5 million to acquire certain assets from bankrupt ATA Airlines in 2008. Southwest's
question: which was the first airline to begin code-sharing agreements with southwest airlines