I use the valve caps that are used on my employers 737 aircraft, they are brass, with a recess in the rubber seal inside for the valve stem pin to rest in and not have a chance of depressing the pin .
SW airlines? I think I saw one landing here in vegas with a flat tire today.
Yeah, SW, every time you change a tire, you have to loosen the valve core to deflate the tire, so you can't put the valve cap back on .
End result, you get a tool box full of the caps after a while .
So I've got them on all of the vehicles .