So right now I am on my flight from Boston to San Francisco, wifi normally costs are $30-50. If you're on the plane and the plane uses gogoinflight wifi service, it can get pretty expensive. But If you open up XCode (using a macbook) and open the iOS simulator then use Safari within the iOS simulator, and launch any website, you'll be redirected to gogoginflight main website where you'll have multiple options to select which internet plan that you want to purchase.
There is an option for $2 that's meant to be used for mobile apps with messaging and the description will look something like along the lines of "WiFi will work only for mobile apps with messaging". But if you purchase this plan & keep Xcode's iOS simulator open, then you should be able to access wifi on your macbook within the flight.
Also, Idk if it might be just me, but my gf tried it and she says that she didn't have to pay when she opened up iOS simulator and connected to WiFi.... so maybe you'll be able to login to WiFi for free without paying!
I wrote this right now instead of paying $50 for WiFi, I only spent $2 :), good luck guys with everything and let me know if this trick works for you!