Yes, I do.
The Dutch blood bank advises not to do "dangerous" activities (where fainting could be a problem) in the 24 hours after donating blood. That sounds like a good rule to apply to flying.
As my donating blood typically happens throughout the week, and my flying mostly on weekends, there's always been a lot more than 24 hours in between those for me.
(Strangely enough, driving is not considered a dangerous activity.
)