You are correct the sides are 1/4" oak and I cut each of these individually. Made a pattern and used this pattern for each of the sides. The pattern took the longest to make and get everything proportioned to satisfaction. Actual time spent on making each was approximately 2 days after getting the "bugs" worked out on the first few.
The wings are 36" long and the width is 5 1/2 " The dark center behind the propeller is 12" across and the lighter plate behind the prop is 8 ". The propeller is 20 inches long and 3 inches wide. Overall height from the bottom of the wheels to the top of the tail is 24 inches. PS just found out I need to make another one for the future grandson.