I'll have a flight with Lufthansa soon and they have an onboard internet service called FlyNet. What is the average speed of that service? If that matters I'll be flying to North America from Frankfurt.
I used Lufthansa FlyNet while flying from Vancouver to Frankfurt in December 2017, paid for it using miles. When the service was available, speed was around 0.5 Mbps, barely enough for web browsing.
However, the real dealbreaker was the reliability of the connection. Over Greenland, the connection was gone for more than two hours. I was a bit annoyed since it happened exactly half-way through the flight (when you are most bored!), two hours are a considerable part of the flight, and I had paid expecting the service would work at all times.
It might have been an isolated episode, and things might have changed in the meantime, but I didn't find it really comparable to Gogo available with most airlines in the United States.