British Airways and American Airlines could be forced to significantly reduce their dominance on three key transatlantic routes to win regulatory clearance for their alliance, according to details of a European Commission recommendation published yesterday.

They may also have to surrender as many as 87 coveted take-off and landing slots currently used at London's congested Heathrow airport for the route to New York.

The EU's antitrust section said earlier this month that the world's biggest airline alliance should be allowed only if it released 267 weekly slots at London's Heathrow and Gatwick airports and cut flights between London and Dallas, Chicago and Miami to help competitors.