"Note: Please choose your home base airport carefully. Number of passengers is low so choose a base with no other airlines (or only 1-2 others for a big airport).", says the game description.
London EGLL: Caledonian Intercontinental (CIC), Dara Airways (DRA), flyLondon (FLO), Lauterjung Logistics Ltd (LLL)
Frankfurt EDDF: frankfurter (FKR), ConAir (CNA), LEONIDAS (LEO), Wings to America (WTA), Frankfurt International (FRI)
and many other examples... just at the game beginning.