What can I do with the little toy plane in the Curiosity Shoppe?

Tap the plane for a closer look.

Its propellers are color coded, and seem to rotate individually.

If only you had a hint about what to do.

Do you remember seeing a very similar plane anywhere?

There is one in the Travel Agency. (Its "sister.")

A poster in the Travel Agency can help you out.

Come back when you've solved the plane poster puzzle.

Did you get the correct numbers? No cheating now.

(SOLUTION FOLLOWS)

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Rotate the blue propeller 3 times, the green propeller 5 times, and the red propeller 2 times.

The cockpit should open to give you a key.