Chris,
Whilst an aircraft is in flight, it's inertia, momentum, kinetic energy or anything else can be measured with respect the the earth, the moon or alpha-centauri and it doesn't make the blindest bit of difference to the aircraft.
A Tiger Moth with a TAS of 70kt, flying into a 70Kt headwind has, according to you, no kinetic energy, yet will fly along (well, it's not actually GOING anywhere!) just fine. The aircraft flys due to the air flowing over it's surfaces. How fast that moves it WRT the earths surface has no bearing on it's performance.
The only relevance ground speed has is that we often have a read-out of it if we have INS or GPS aboard, and the difference between that and our TAS is the wind. Changes in that relationship indicate changes in the wind, which IS relevant as that is the air we are flying through. But GS in isolation (and therefore Momentum, Kv or anything else reference the earths surface) has no bearing on the aircraft at all.