I've not noticed any buffeting from wind whilst on the trike's, so I'd guess that it doesn't affect them much.
Last week when a lorry passed I personally got buffeted but it didn't affect the trikes handling even with panniers and a dog trailer
,
whereas the upright cyclist in front came off!
(He was uninjured but really pissed off
and a bit muddy).
The lorry gave plenty of space when passing, it was just the speed that caused the buffeting.
To his credit he stopped and walked back to see if the cyclist was OK.