I have non UST tyres on Stans rims, should I just reduce pressure a little, as I always did with tubes, or drain all fluid, and refill on arrival?
Anybody got any experiences, or horror stories?

urban myth

Modern planes are pressurized to an equivalent altitude of about 6500 to 7000 feet.When you ride your bike up a mountain, do the tires explode when you get to the height?

The only time the pressure of your tires will make the slightest bit of difference is if there is a sudden pressure change, and if there is, the last thing you are going to be worried about is whether your tires have burst.

If you are that worried, let a bit of air out of them. No problems.

Good point! IGMC 😳

Does the plane let its tyres down when its taken off?

No

Then you'll be fine I guess.

One thing though, I used Stans for ages and went to the Alps last year. a month before I changed my tyres for fatter ones and popped some new stans in.

When I got back and changed by fat tyres for not so fat ones, the Stans had solidified into a ball of rubber. It had only been in the tyres for a month and a bit but before this was in the other tyres for nearly a year and was still fluid when I changed them over.