Incheon is one of the best airports in the world, and KE and OZ are the featured airlines there (all other airlines must use the satellite terminal). This airport has it all - transit hotel, several spas (including a Korean Jimjilbang Spa in the basement), free internet, TV lounge, the HUB public lounge, all sorts of banking facilities and even a hospital.

I insist on flying Asiana (OZ) and always use the free day-use hotel as most of their US-bound flights require a lengthy transit. Neither KE or OZ really advertise this service, but all you need do with OZ is to contact their local offices after booking to reserve the hotel (all classes).

Asiana also features a coat check service for individuals traveling in winter to tropical destinations (who needs a ski jacket in Thailand?)