Emirates and Qatar price per volume, the "big pack" is 100 MB. Using an iPad and doing quite some surfing this is sufficient. Using my PC and all the Outlook downloads the 100 MB are used up quite quickly.
Lufthansa, American, Delta have it based on time. Much more relaxing. With all of them you can also use roaming partners such as Orange or Boingo.
For US domestic flights there is something like a 1 year-all-airlines package, which I believe is USD 39 p.m. I had it this year when during a couple of months I was doing many US domestic flights across DL, AA and UA. Quite neat to just log on.
The smartest solution yet I have seen is - believe it or not - Saudia. On a recent flight on their B789 the way it worked was that pax entered their name and flight number on a dedicated mobile app, which gave them a code, which in turn then gave free WiFi access. This code was only given to J class pax.
All these carriers are smart enough to block access to sites like Netflix or the iTunes film store.
Having said that, the prize for the most brainless design of a WiFi service does not go to an airline, but to Eurostar.
Other than that thanks for the Trip Report. VEry exciting, I am obviously curious how you got to travel on the delivery flight.