Sig Something extra or the 4 * are great plane's and very easy to build and fly.
Heres something else for thought since you like war birds The House of Balsa line are easy to build, small enough to fit your needs for room & buget and they fly quite well when all done .The T-6 or mustang both are great little planes with a 25 size engine, plus you have your choice of adding the gear or not.