Thanks for the reports guys. With your help we were able to narrow down what was causing these disconnections on our end. It's going to require a hotfix to resolve so the fix won't be immediate, but we'll roll it out as soon as we can.
For the time being, try to pause for a moment before you switch into flight form and fly off. That should reduce these kinds of disconnections.
My disconnections don't only happen on my druid so I'm not sure that will help me, but at least they recognise there are issues going on with the game and they will hopefully be able to follow those up as well and do something.