OTAs operating in the European travel market find themselves in an interesting position in 2018. On the one hand, these intermediaries have been instrumental in the maturation of the region's online travel marketplace, and the key players in the category are household names among European travelers.

But increasingly, the landscape has shrunk to the point where, in the battle for OTA bookings, just one or two players compete, making it extremely challenging for smaller OTAs to stay in the game.

As importantly, OTAs are now overshadowed in certain segments by the online supplier-direct channel, as a result of suppliers' success in developing and promoting their own online booking platforms.