On our 1.10.2 FTB Beyond server
rftools- 1.1x-1.6.6

The flight that the flight module gives persists despite being far outside range of Environmental Controller; it also stays and allows players to keep flight after relogging onto the server, and after planned/forced server restarts.

Does it persist forever? How long did you wait for it to timeout?

While testing, about 30 minutes. Players on our server were able to fly for quite a while, the only way they lost flight was dying.

Thank you for taking the time to create this issue, as we're no longer supporting versions below 1.12, I'm going to go ahead and close it but if this bug seems to continue over to newer versions, please do report it again so we can investigate the issue further.