During the Second World War, the Royal Air Force $($RAF$)$ had many foreign pilots speaking differ$-$

ent languages and more or less trained to fly the different types of aircraft used by the organization.

The RAF had to form pilot$/$co$-$pilot pairs $($crews$)$ for every plane with a compatible language and

a sufficiently good knowledge of the aircraft type. In the following table, every pilot is character$-$

ized by a score between $0($worst$)$ and $20($best$)$ for his language skills and experience with different

two$-$seat aircraft.