Start with the aircraft’s theatre
Theatre matters more than a generic weathering recipe. Desert aircraft get dust and fading. Pacific aircraft often show sun, salt and chipped paint. Eastern Front aircraft can show mud, snow, temporary whitewash and rough field repairs. Bombers collect exhaust, oil and operational grime.
Exhaust staining
Build exhaust staining slowly. Use thin layers rather than one black stripe. Radial engines, inline engines and heavy bombers all stain differently, so check photos of the aircraft type.
Paint chipping
Chipping is easy to overdo. Focus on high-traffic areas: wing roots, cockpit edges, access panels, cowl fasteners and leading edges.
Oil, fuel and grime
Oil streaks should follow airflow and gravity. Keep them subtle unless the real aircraft was notoriously dirty.
Fading and scale effect
Fading can be shown by slightly lightened panels, uneven camouflage and dusty filters. Avoid turning every colour pastel; the goal is operational wear, not a cartoon effect.