Air France-KLM and Delta Air Lines, the leaders of the SkyTeam global airline alliance, are to announce plans on Wednesday to expand their presence at London Heathrow, the main European gateway airport for air traffic across the North Atlantic.

The two airlines are also planning to deepen their bilateral alliance into a full-scale profit and revenue sharing joint venture, as they prepare to take advantage of the commercial opportunities arising from the US/European Union “open skies” deal to liberalise North Atlantic aviation, which comes into operation next March.