I was flying ORD-IAH-MEX on sunday. ORD-IAH worked great on a 767. On IAH-MEX, internet should have worked over the US. When I tried logging on, I got an alert my subscription wasn't valid for my location (or something along those lines). Of the 6 flights I've been on since buying, 2 have worked (pretty well actually), 2 did not work with my subscription/recognize my subscription, 2 had "internet unavailable" including my entire MEX-EWR flight (no compensation offered) - (FA said something about wifi upgrades to the aircraft?)