DALLAS (AP) — Herb Kelleher, the joke-cracking, charismatic leader of Southwest Airlines Co., will serve one more year as chairman of the airline he helped create and then resign next May, the company said Thursday.

Southwest also extended the contract of Chief Executive Gary C. Kelly into 2011, and said President Colleen Barrett would step down next July.

Kelleher, 76, and Barrett, 62, will remain Southwest employees for five years after leaving their executive jobs, working full time at Dallas headquarters, the company said.

Kelleher said he and Barrett had wanted to step away from the executive grind and were not pushed out. Kelleher said the departures were part of a succession plan launched in 2001, when he resigned as CEO.

The transition to a new CEO proved rocky. Kelleher's successor, James F. Parker, fought with Southwest's unions and resigned after just three years, citing personal reasons.