Originally Posted by
43Inches
Don't forget that China uses meters for altimetry and Russia below flight levels is in meters. Considering a very big percentage of the worlds pilots are from the USA, China and Russia, you can safely say that overall standardization of the majority of pilots on one system is still a while away.
In any case, no one I know seems particularly fussed. Toss a few warbirds, vintage and just plain old aircraft into the mix and to be a competent pilot these days unit conversions of all kinds are just part of the training.
What isn't are the ATC procedures - and if YT videos are any guide, as far as I'm concerned, the USA are welcome to theirs and good luck to them.