Australian tennis great and Christian pastor Margaret Court has publicly announced she will stop using Qantas "where possible" in protest at the airline's promotion of same sex marriage.
"I am disappointed that Qantas has become an active promoter for same sex marriage," Perth resident Ms Court said in the letter published in The West Australian newspaper.
"I believe in marriage as a union between a man and a woman as stated in the Bible.
"You statement leaves me no option but to use other airlines were possible for my extensive travelling."
The nation's other major domestic airline Virgin and its founder Richard Branson also support gay marriage.
