Aircell offers $35/mo rate for unlimited use of its Gogo Inflight Internet on whatever airline you find yourself on: I can't see how this helps the airlines, given that it reduces loyalty to a specific airline instead of the overall availability of Internet service, but I imagine it will trigger a flood of frequent-flier signups.
The service is contract-free, but automatically renews each month unless canceled. The pass can be purchased onboard most Gogo-equipped airlines (those with a fair number of planes in the air) or in advance. (The pricing page says that it only works on four airlines, but the press release says that it works on all Gogo-equipped airlines.)
Gogo's other 30-day pricing seems a little strange now. $40 buys you a 30-day pass across all airlines, but without an automatic renewal; $30 gets you access on a single airline for 30 days.