This website tells about full size boats from paper during the later half of the 19th century.
Good resource about paper boats and boat building. Paper boat tutorial from a book published in 1887 is interesting (kcupery.home.isp-direct.com/paperfold3.GIF).
Boat building tutorial with step by step photographs can be found in laits.utexas.edu/hebrew/personal/toolbox/acm/boat/boat.html
These resources should be great help in helping kids making paper boats and play with them.