Apparently, most American's aren't too keen on the idea of paying $13 just to be able to watch Youtube for a couple hours and would rather entertain themselves for free. Of course, even if adoption is only 10% of all airline passengers, it is a worthwhile investment. All major airlines have signed contracts with in-flight Wi-Fi providers, the vast majority being Aircell's Gogo service.
But the cost is still prohibitive. For short flights, it's $4.95, but anything more than a couple hours costs $12.95 (users can also buy a full-day pass if they have connecting flights, for the same $12.95 price).
Another interesting statistic about in-flight Wi-Fi usage is that a lot of people are using non-laptop devices. While portable computers do still account for well over half of all connected devices, a substantial amount of customers are connecting their iPhone, iPad, or Android device through Gogo's service.