Continental Airlines said it's going to launch twice-daily flights from London Heathrow to both Newark and Houston, taking advantage of the open skies agreement between the U.S. and the European Union signed earlier this year, and by Continental's acquisition of the necessary slots at Heathrow Airport. Continental will continue to fly to London Gatwick, twice daily from Newark and once from Houston and Cleveland. The flights will start March 29, subject to government and slot approval. Continental's Heathrow flights will operate at Terminal 4, which will be the future base for all SkyTeam carriers operating at the airport. Shares of British Airways , the dominant trans-Atlantic operator at Heathrow, slipped 1.6% in London.