An airport fitness center is an interesting idea but I don't think it would be for me, mainly for logistical reasons. I'm simply not that interested in making sure that my bag is safe, that I have proper workout wear, and that I have time for a shower and that one will be available exactly when I need it.

If I'm in an airport, I'm headed from home to somewhere where I'm going to be very active (and have probably been rushing around preparing for the trip), or I'm headed home from somewhere where I've been very active, or I'm rushing between two places and looking forward to the downtime. Thus, if I have 2-4 hours in an airport, I'm going to go into a lounge and relax. If there's no lounge, I'll walk around a bit and then sit down and relax. If I have more than 4 hours and the proper entry credentials for the country I'm in, I'll exit and explore.

But I don't fly nearly as much as some people here. I could imagine just the right set of business travelers who frequently have 3-hour connections and would like to use the time to work out, especially if the equipment is better than what they'll have in their hotels. But I think it's a very specific niche that would be difficult to cater to, given the costs involved and the need to make the facilities easily accessible to people (if they will be airside, then depending on the airport they may be accessible only to people in a specific terminal).

Seth