Jan. 3 (UPI) -- Southwest Airlines co-founder Herbert Kelleher died Thursday, the company announced. He was 87.
The airline did not reveal the cause of Kelleher's death.
"Herb was a pioneer, a maverick, and an innovator. His vision revolutionized commercial aviation and democratized the skies," Southwest Airlines said. "Herb's passion, zest for life, and insatiable investment in relationships made lasting and immeasurable impressions on all who knew him and will forever be the bedrock and esprit de corps of Southwest Airlines."
Kelleher founded Southwest Airlines with Rollin King, famously using a cocktail napkin to brainstorm their ideas in 1966.
Based in Dallas, the airlines first flew only to cities within Texas but expanded to neighboring states in 1979. The airline currently flies to 99 U.S. cities and 10 destinations outside the United States using a fleet of more than 750 jets.