Keep in mind the weight you are not dealing with here. none of your assemblies, fuselage wing panel should even approach 50 pounds. under 40 more like it. likely the table will weigh more than the work. I am building two particle board tables. with 2x4 structure underneath. 30" by 84" each. width is minimum allowing only an inch extra. needless to say I will need some stops to keep it from sliding off and damaging itself, but I need space- building in an attic.
I am viewing the tops as disposable, paint and layout, holes if I need clamps somewhere. Welding burns scorches, screw jigs supports and such. 1/2 ply for lower shelf and gussets to stiffen legs. Particle board mdf type sheets will lay flat and if supported will stay flat and not warp.
but in the end you need to make what works in your space and use resources and techniques you have.
good luck and have fun