Doke has quit to join computer giant Dell in the newly created role of V-P communications, heading financial communications, media and community relations, employee comms and public affairs.
He is succeeded at AA by MD of strategic comms Gus Whitcomb, who has been promoted to acting MD of corporate communications.
Whitcomb has held various PR roles at Aloha Airlines, America West, Greenwich Air Services and Neale-May & Partners.
He said his main task is to 'try to get up to speed with a lot of issues that I haven't been directly involved with - we're looking at every angle of the business'.
He added: 'We're running a company that is trying to avoid financial disaster. The emphasis is on creating a smooth transition.'
Doke starts his new role at Dell on 10 March, reporting to V-P of corporate communications Elizabeth Allen.
The move quashes rumours that Allen would be replaced.
Dell said last year that it was looking for a global marketing and communications leader to sit above Allen, but the company has since called off the search.
Reporting to Doke will be director of corporate communications Barry French, director of public affairs Cathie Hargett and director of internal communications David Frink.
Doke was at American Airlines for four years, most recently dealing with the ramifications of 11 September and the economic blight of the airline industry.