I seem to have a major problem with slower speeds, i have a lot that i shot at 1/200th to 1/320th but i seem to miss a heck of a lot of shots they are really OOF and even though it was a bright day, i seem to make a lot of the planes dark and the skies ok, even if i try spot metering or centre-weighted on the plane.
I wonder if the lens has a focus issue, as i had a similar problem at Biggin Hill and A1 GPrix only since gettting the VR lens.