Gruen Airport? with Plane on Crystal, Can anyone tell me about this piece

Bought this on Ebay, have not found another like it, want to know the year, this is a 15 Jewel , swiss movement Gruen , I assuming avaiation because of the four engine plane painted inside the crystal, would love to get more information, such as year, or actual watch model, also, is there any others like this, this watch is a manual wind up and still works!!