> It's similar to how in flying, we still use feet/flight levels, and actually a few places have migrated from metric to the more conventional imperial system.

It hasn't stopped the conversion of most other aviation measurements to metric. Runway dimensions, visibility and separation distances are in meters, temperatures are in Celsius, atmospheric pressure in hectopascals, fuel is in litres, mass is in kilograms. Frequencies are in Hertz. At least that's the case in Australia. Pretty sure Europe is similar.