British Airways is facing a "fight for survival," its chief executive Willie Walsh said in an article in the airline's staff newspaper.

"It's critical that we all recognize that the diagnosis for our airline is now critical," Walsh wrote in the newspaper.

He said the crisis facing the aviation industry "has never been more serious."

"There has been a significant shift in consumer attitude, with people wanting more and paying less. And things are getting worse. We haven't yet reached the bottom and everything points towards a protracted downturn," he said.

Walsh said some areas of the business had made progress on pay and productivity negotiations but elsewhere change "has been slow." He has set a deadline of June 30 to complete talks with unions.

Last month BA slumped to a record loss, cancelled its dividend and said tough market conditions made it impossible to give any guidance for the current period.

Shares in BA, which have lost 28 percent of their value over the last year, closed Monday at 155.5 pence, valuing the business at GBP1.79 billion pounds (USD$2.95 billion).