"Plastic" is hardly the right word, especially if it makes you think about LEGO bricks or Barby dolls. Call it rather "graphite composite" or "carbon fibre" or "CF", then we will know, especially if we have an expensive fishing rod.
Carbon fibre was invented back in 1962 by the Royal Aircraft Establishment in Farnborough, England (RAE, the British NASA you might call it) and has since then been widely used in the aircraft industry. In the civil sector Airbus has used it for tail surfaces for 25 years. Beechcraft made a biz turboprop, the Starship, entirely out of CF some 10-15 years back. Porpellers and helicopter rotor blades are mostly made of CF these days. A lot of secondary structures such as landing gear doors, tail cones, wing tips, winglets etc. have been made of CF on just about any airplane for many many years.
Very large structures are still difficult (and therefore expensive) to make. CF structures must be moulded in one operation and cured under high pressure and temperature.
In military aviation CF has been even more widely used. The General Dynamics (now Lockheed) F-16 fighter was probably the first fighter to make extensive use of CF already in the 70'es. The MDD AV-8B Harrier II has flown with CF wings the last 15 years.
Rockets, satellites, space ships, race cars etc. have all made heavy use of CF since it was invented. My model aeroplanes are made entirely of CF except the fuselage tail boom. It contains the radio receiver antenna, so it is made of aramid fibre which unlike CF doesn't shield for the radio signals which control it. The nose cone on any airliner is also made of aramid fibre since it covers the weather radar and needs to be transparent to radio waves.
For 30 years is has been possible to make a 737 size wing out of CF. The only problem is if it is economically feasible.
You can paint CF just like any metal. If in doubt, have a look at any Airbus fin. In fact it MUST be painted. Otherwise its black color, when parked on a hot day in sunshine, would make it so hot that it loses its strength.
Most modern glider airplanes are made of CF (plus glassfibre and aramid fibre), and therefore they are normally painted all white, and never ever painted in dark colors or left unpainted. Often on gliders it is not real paint, but a mixture of paint pigment and a plastic called gel coat which is sprayed and cured in the moulds even before the CF structure is built up in the mould. But that's only a way to make a perfect aerodynamic surface with exactly the same shape as the mould.
Always keep your number of landings equal to your number of take-offs