Mr Walsh also blamed politicians for being "afraid" of tackling the issue of airport capacity.
He said: "I think it is fear on the part of politicians. They are afraid to tackle tough issues.
"It (expansion) has been kicked into the long grass and I think it will be sitting there for a considerable time."
He envisaged that there would still be only two runways operating at Heathrow even as late as 2050:
"New runway capacity is required, but I don't believe that capacity will be provided....This issue is too difficult for politicians and governments to deal with. We are positioning our business on the basis that there will be no expansion," he added.
More top news
Ex-London mayor Ken Livingstone says he is sorry for the "disruption" caused by his comments that Adolf Hitler was a supporter of Zionism.
Kickstarter group asks for public donations to fund replacing Tube ads with pictures of cats
Sir David Attenborough opens Woodberry wetlands in Stoke Newington