Almost the entire world still uses nautical miles, knots (speed), and feet for aircraft altitude. I'm pretty sure most airplanes all use AN hydraulic fittings, which are based on Imperial sizes (correct me if I'm wrong there).

Also, people always say that the US is the only country that uses feet, pounds, miles, etc. But there are a lot of other countries that still use those units, or at least understand them, even if it's not an official unit. I even work with engineers from China who use and understand Imperial units. I also visited a friend in Ireland who had a (pre-digital) scale that measured weight in stones.