1) Do you travel frequently?
2) If so, how many hours are your layovers?
3) What do you do during those hours?
4) If you could gain personal/professional development during that time, would you do it?
1) no, but I once did
2) zero when possible, only if there is no direct flight available at all did any of the companies for which I traveled ever book a layover
3) it depends on the company whether my travel time is billable or not, so if it's not, there's no way that I'm going to do anything work-related while completing my travel
4) no, travel time is considered a complete loss, since having access, quiet, no distractions, mood, etc. is never guaranteed. I wouldn't count on this time as "available" to me under any circumstances. I bring a book, and even then I don't read it half the time.
I don't expect that I'm like everyone else. I do not expect that you will find frequent travelers on CFL simply because 90%+ of people here aren't even up and running yet. This might be a better question pushed through travel agencies who book on behalf of companies.
That said, my anecdotal impression is that unless forced to work, most people either use travel time as an escape, or already have a habit. I think you might find more interest from the airlines directly in offering programming for their in-flight media screens, than to approach consumers directly.