The super high gloss finish on transport repaints is the result of the ultra high gloss urethane's. Imron, a Dupont product is the best example I can think of, but really not the paint they use... A two part polyurethane mixed together with a catalyst and other additives, sits for about half our to let the chemicals interact with each other before applying. Boeing and other larger completion centers use electrostatic guns enabling the paint to flow smoother and finer with better adhesion qualities. The high gloss is a protective layer that forms on the top surface upon curing. Unlike cars...this is not a clear gloss coat. This paint is notorious for it's "Wet Look". The downside of polyurethanes is that they tend to oxidize much like a gel coat on a boat. Polishing will bring it right back up but eventually another repaint will be in order. This oxidation is evident on Southwest Canyon Blue. The reds in the blue paint fade first. With the high use of composites it is necessary to ensure good coverage to prevent water invasion. So all wing panels and control surfaces get the paint. The torque box sometimes receives corrugard,an aluminized coating to help reduce fuel temp in the wing. MD
-80's, DC-9's used to polish wing skins as the aluminum they used held a shine due to it's alloy.
The only planes I've actually seen get polished are corporate jets...they sometimes use a Teflon spray, helps promote easy bug splat removal. Sometimes heavy iron will bright work their leading edges and nacelles, but rare. Airbus sometimes paints leading edges and installs Teflon tape on the leading edges. The A380 has painted leading edges on some of the surfaces which surprises me due to the size of the radius of the leading edges.