The new Nikon 70-300 will be more than useful for airshows. I think a zoom to 400mm is perfect but 70-300 is adequate. I sometimes use 70-200 with 1.4X (280mm) if airshow is going to be crowded because of lightweight and compact. Max aperture no problem on normal days but if dull/raining will have problems but would you want to be out in that weather anyway - I know I wouldn't. Solution is to increase ISO, use faster lens or go home
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