In Europe the airlines I know (Swissair, Lufthansa, Austrian, Sabena, Crossair) all use miles (not km). Still - there are (very) small differences in mileage credits - even on code-share flights (operated by the partner) for example Delta/Swissair or Lufthansa/SAS and United don't credit exactly the same mileage (so depending on the name of the airline on your ticket you may get different mileage credited than others on the same flight), but the difference seldom exceeds 1 per cent (and as we all now the difference of the ticket-price on the same flight often exceeds 200 per cent ...)..