This indicates a professional-grade scanning quality. Most standard home printouts are 300 DPI; 600 DPI ensures that fine lines, rivet details, and cockpit markings remain sharp even when scaled up.
Before folding, lightly "score" the fold lines with a blunt tool (like a dried-out ballpoint pen) to create crisp, clean bends.
Use a quick-drying PVA glue or specialized papercraft glue to avoid saturating and warping the paper.