As I said in my WhiteWings guide…

In addition to the Core Volumes, Whitewings released three volumes of balsa+paper gliders. These models use balsa wood as the fuselage and the planes' wings and other parts come pre-cut. These models are massively easier and quicker to build than their paper counterparts. However, they are more expensive and contain only six models per series. However, if you're an uncle or aunt showing up for a weekend of fun with a niece or nephew, you can't do much better than having one of these series in your suitcase.