This is something I found on LifeHacker which might come in handy…
How to Lie, Cheat, and Steal Your Way to a Perfect FlightInternet access isn’t particularly cheap when you’re getting it on an airplane. In fact, the cost of access for a single flight can be comparable to what some people pay for basic DSL for an entire month. We’ve looked at how to get cheap or free inflight wi-fi before, but one tip has stood up to the test of time.
Because you’re less likely to consume the same amount of data on your mobile phone as you would on a laptop, your phone gets a cheaper rate. It’s not much cheaper, but it usually works out to about 20% off. If you want to pay this lower rate but still use your laptop (or tablet, which is considered a computer) you just have to identify your web browser as a phone when you sign up. This is pretty easy to do. If you’re running Safari, you can select your browser’s user agent from the Debug menu. If you need to enable the Debug menu, you can do so with the following terminal command:
defaults write com.apple.Safari IncludeDebugMenu 1
Changing the user agent in Firefox is also pretty easy if you install the User Agent Switcher add-on.
Once you’ve identified yourself as a mobile phone and signed up, you can switch back to a normal user agent and use the connection normally.