At first glance the pairing of both the USA and Canada on these Royal Air Force shoulder patches seems odd. When we discover that they were worn by Americans in the RAF before the USA became a military ally, it all starts to make sense. The earlier, more rounded pair feature a distinctly more American eagle while later versions were more clearly derived from the RAF bird.
Under the rules of the Commonwealth air crew, other nationality titles were often worn. The patches below were made in Canada but worn under the empire training scheme.