The Boeing Connexion system was satellite-based (thus high latency), cost $500K per plane, and weighed 1000 pounds.

The Gogo equipment costs $100K per plane, and weighs 100 pounds. It's ground-based, with stations using EVDO equipment that point upwards. Presumably the EVDO base stations cost a lot less to implement and operate than running a satellite uplink, since that's tried and true cell phone tech.