The models that I assembled as a kid -- rarely planes, most often monsters and super-hero figurines -- looked awful and were unstable, because I rushed things and got sloppy. I wouldn't wait for the glue or the paint to dry. Ultimately, we blew these up with firecrackers, and good riddance to 'em.
When my young son showed an interest in building these things, I helped him, figuring that with decades of maturity on my side, I'd do better. Wrong: I was just as impatient and reckless. No firecrackers this time, but my results were substandard. The ones he did by himself were far better. (They had this new, "safety" glue that didn't hold anything together. We had to go back to the old, pungent, lethal kind.)
I helped him assemble a U.S.S. Enterprise that turned out okay, though the engines kept falling off. I finally filled the hull with foam and put some rods in there to provide support, and that did nicely. Darn design was never meant to survive in a a gravitational field like ours.