I probably spent a little too much time on this for being just a box model, but I am pretty happy with the result. I worked from a reference and tried to apply some of the things that I learned with pivots and duplicate linked. I used some extra things that I already knew about like the mirror modifier, beveling, and loop cut. I am excited to keep on learning!
As a box model, I think yours is perfect! I am considering doing mine again so I can practice a faster initial modeling stage. I tend to go overboard when I don’t need to.
Great job! A neat model of a biplane. I like it very much . I for my part have skipped this challenge for now, but will definitely catch on it later.