I do my scaling on the printers at Office Max. They go up to 400% and down to 64%. The paper can be up 11"X 17".
I calucate the ratios at home and punch them into the machine. It generally takes maybe two passes for the wing, two for the fuse, and one for the tailplane. I tape the pieces together and get itdone for under a dollar.
Doing the whole plan in one pass at Kinkos is over $10 - unacceptable.