Re: Noah called, he wants his units back.
In gliding, the units used are metric. (Probably something to do with the fact that gliding was developed as a sport mainly in Germany).
Not true everywhere: the units used in gliding depend on where you are and its quite messy.
European gliding uses metric units.
In the USA they use feet, knots, nautical miles and pounds weight. Their airspeed indicators are upside down: zero at the top, cruising speeds at the bottom and some older aircraft still use mph rather than knots. I have no idea why they do this when speedometers in road vehicles are the right way up. Everywhere else I've flown the ASI has zero at the bottom and normal climbing and cruising speeds at the top.
In the UK its quite a mixture. Gliders airframes are metric for length, weight and wing area, instruments are ICAO (knots for speed and rate of climb, altitudes in feet), but distance is a mess. We use statute miles when talking to ATC but, because the badge scheme and racing tasks are metric, we think in kilometers for all cross-country flights and related distances.
BTW, until shortly after WW2, all European aircraft had metric instruments, but some time, in the 50s IIRC, all powered civil aircraft throughout the Western world adopted ICAO navigational units (knots, feet, statute miles) along along with their air traffic control systems.