A recent trend in aviation markets is the emergence of airline alliances. O
ne could argue that the emergence of alliances is a continuation of the pro
cess of concentration and consolidation that was first characterized by the
emergence of hub-and-spoke networks. The international aviation market is
still subject to regulation, and airlines may only have the opportunity to
extend their networks to foreign countries by entering an alliance agreemen
t with a foreign airline. But also in fully liberalized aviation markets, a
irlines are likely to enter alliance agreements. The literature shows that
passengers are likely to be better off if airlines enter alliance agreement
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