Susan,

I wouldn't be surprised if Catholics pioneered airport chapels, although today's "prayer rooms" or whatever they're calling them, do have a decidedly different flavor than they used to. There is nothing in Church teaching that I am aware of that addresses the topic of using what modern airports have installed.

I would say that if you feel comfortable there and find them conducive to prayer, then pray there, but if you feel uncomfortable, don't pray there and maybe drop a line to the airport and explain why you don't feel comfortable praying there.