Translation:Did you see the cows in the airplane?
It is ambiguous, but most likely you were in the plane and saw the cows that were in the plane as well or you saw cows inside a plane (and your position is not defined). In Dutch when you are inside something and look outside, a native speaker would almost always use kijken vanuit I think, e.g. Heb je de koeien vanuit het vliegtuig gezien (Did you see the cows from the plane). In that sentence there is no ambiguity: you are in the plane and the cows are not in the plane.
1) wait until Duolingo offers the Russian course, 2) complete your tree and 3) watch the "Peculiarities of the National Hunt" movie (in Russian). I won't be giving you any spoilers about The Cow (it IS there %), but with or without it, the movie is well worth to be seen on its own. It's a comedy. Quite self-ironic :)