Re: Another mighty initial thrust idea
"At the point of firing the rocket, before the plane has any speed relative to the rod, it cannot overcome even a small force due to friction"
I think this is where you're going wrong. If this were true then _nothing_ would be able to accelerate from zero and move away from its initial position. Think about it; anything accelerating from zero has to start by moving very slowly, so for example, a parked (stationary) automobile has to overcome not only air resistance but the rolling resistance of its tyres* to start moving. The fact that automobiles accelerate much less quickly than our a rocket doesn't seem to stop them though (you need the M25 for that).
* As a pneumatic tyre rolls it is deformed and this uses energy.