Just built my first plane and it flies ok - without SAS. Once you have SAS enabled the control surfaces start rapidly flapping up and down like the plane is a Kolibri - and this in turns leads to a wildly fluctuating lift-drag ratio. Not good for handling the plane. I also had a case in orbit which I could not easily reproduce, where I had a medium sized vessel in orbit with a Poodle engine and the small 1 kerbal pod, without RCS or an reaction wheel. Once I throttled up my engine (which ha