Aviation has always been a mixed bag of units.
At least for the last 40 years that I've been involved, temperatures were nearly always C (EGT and TAT/SAT), distances and speeds in nautical miles (or Mach, which is dimensionless), and altitudes in feet. Three different systems
Knots or nautical miles is really weird since, outside of aviation (and a handful of sailor types), hardly anyone knows what it means even if they've never used metric.
However the inertia of the system is such that I doubt it'll ever change, at least not during my lifetime.