Would this SFX collection be valuable to you?:
International Airports ambience with walla and intercom announcements where possible.
China, India, Europe, UK, US, Australia, Russia, Japan, South America, Central America, the list goes on...
Also, keep in mind that at least in the US, music is everywhere. I've never been able to record in a US airport due to music and or TV playing in the background. I still can't understand why we can't have spaces in this country that don't have music.
The elements would need to have a good amount of separation, ie. wallas not tied to p.a. announcements, since those often need to be kept on their own pre dubs and split out for foreign versions (M&E). But yes, if properly mastered it would be a very handy collection of sounds.
I personally have not come across the need for these sounds in my projects so far, but it is certainly the type of thing that when you need it quickly it would be a big pain to get, so I bet it could be useful too many people.
This library is already out there http://www.soundscalpel.com/soundeffects/pack/airport-internal-ambiences/ Again I don't have it so I have no review as to its quality, but there is lots of room to cover more and varied airports worldwide.
I would say go for it.