> Maneuvering for a rendezvous (intercept), given 5-40 hours time, is very cheap in terms of ∆V (fuel used).
Only if you're in approximately the same orbital inclination. Plane change maneuvers once in LEO are very expensive in delta V.
The attacking bird needs to raise apogee to GEO anyway - after that the plane change is relatively cheap. They might not even raise perigee.
The attacking bird needs to raise apogee to GEO anyway - after that the plane change is relatively cheap. They might not even raise perigee.