@kiro: Do you have a save file that shows the problem? What version of the game was this?

Thank you!

It's 1.6b5

Sadly I left the system and upon reentering the escort was gone.

Probably the same as http://ministry.kronosaur.com/record.hexm?id=4116

Looks exactly the same as the record mentioned by giantcabbage.
I uploaded 2 save files of the same game were I reproduced the bug.
The escort docks with the drake and starts its enginges and it is stuck.

I believe I've also reported this one. Must be fairly resilient.