Thanks! I found it humorous that all three were started by the military of another country (UK, US, and West Germany, respectively). I don't think those really

Thanks! I found it humorous that all three were started by the military of another country (UK, US, and West Germany, respectively). I don't think those really support the idea of there being network effect benefits to opening a new airport. The Wikipedia entry for Frankfurt Haan makes it sound like it's been a money loser for at least 15 years, and the one for Beja says "the airport has no scheduled passenger flights".