I've had cramps and pins and needles for a while now. Slightly worried about what's going on as well.

Genetics must play a part. Poor circulation runs in my family. My mother's hands go white when it's cold. My feet go pale and icy cold when I stop exercising. I need rest to heal the tendons, but movement to get blood to them :/

I suppose it's everything in moderation, seems like the healthiest option.

And some alcohol to thin the blood. Maybe that'd help circulation on the long haul flights, providing you weren't dehydrated.