Tom
So glad you have got an improvement.
Now - Lets just put a spanner in the works
When shooting aircraft with props and rotors, you will quickly realise that your high shutter speeds are freezing all the action giving the impression that helicopters are falling out of the sky and prop jobs have stopped engines, neither of which does much for the photo.
Solution ? Drop the shutter speed below 100th sec and practice "panning"
that is a technique of SMOOTHLY following the aircraft through the lens before, during and after the exposure, if you get it right the aircraft will still be sharp but the props/rotors will appear lifelike ie turning. Experiment with the shutter speeds for best effect. When panning you also get rid of distracting backgrounds as they become a blur.
Simples
Have Fun