TRAVELSouthwest AirlinesAdd TopicSouthwest Airlines at 50: A birthday photo albumUSA TODAYWhen Southwest started in 1971, it flew just two routes: Dallas-San Antonio and Dallas-Houston. That's not the only thing that was different back then: The flight attendants wore hot pants and go-go boots. Click ahead for more photos from the airline's history.Southwest Airlines, WieckSouthwest Airlines co-founder Herb Kelleher at the launch of the airline's Boeing 737-300s in 1984.Southwest AirlinesA Boeing 737-300 aircraft in Southwest Airlines' historic colors.Southwest Airlines, WieckSouthwest planes at one time featured lounge-style seating, with passengers facing each other.Southwest Airlines, WieckIn 1992, Southwest co-founder Herb Kelleher famously arm-wrestled Kurt Herwald, the chairman of Stevens Aviation, for the the rights to the phrase "Plane Smart.'' Kelleher lost.Southwest Airlines, WieckSouthwest Airlines flight attendant uniforms in the 1990s.Southwest Airlines, WieckSouthwest's planes got a new look when the airline turned 30 in 2001.Southwest Airlines, WieckKelleher kissed the Liberty Bell to mark Southwest's new flights to and from Philadelphia in 2005.Southwest Airlines, WieckSouthwest had Shamu planes to celebrate its partnership with SeaWorld.Southwest Airlines, WieckSouthwest featured baggage handlers in its Bags Fly Free advertisements.SWA, WieckSouthwest announced its acquisition of AirTran Airways in 2010.SWA, WieckBoeing unveiled Southwest Airlines' first 737-800 in 2012.Stephen Keller, Southwest AirlinesPassengers from Southwest Airlines Flight 906 β the carrier's first to Montego Bay, Jamaica β arrived from Baltimore on July 1, 2014.Southwest AirlinesThe company's latest look features a heart on the belly of the plane.Southwest Airlines, WieckSouthwest made its maiden flight to Havana on Dec. 12, 2016.Southwest AirlinesSouthwest Airlines added the Boeing 737 Max 8 to its fleet in 2017.Southwest AirlinesSouthwest Airlines' website paid tribute to co-founder Herb Kelleher on Friday, Jan. 4, 2019. Kelleher died Jan. 3 at age 87.Southwest Airlines (screenshot)Southwest Airlines debuted service to Hawaii in March 2019.Sandy HooperSouthwest Airlines Boeing 737 Max aircraft are parked at the Southern California Logistics Airport in Victorville. The aircraft was grounded after two fatal crashes in five months, and Boeing is trying hard to present itself as unfazed by the crisis that surrounds the company.MARK RALSTON, AFP/Getty ImagesTravelers exit their Southwest Airlines flight from the back of the aircraft in October 2019. Southwest Airlines offers front and back deplaning out of certain airports across the country.Harrison Hill, USA TODAYBaggage is loaded onto a Southwest Airlines plane Aug. 12, 2020, at Mitchell Airport. in Milwaukee. The COVID-19 pandemic severely affected multiple airlines and the travel industry as a whole.Mark Hoffman, Milwaukee Journal SentinelFeatured Weekly Ad