A plane is made of three major components: the airframe, or fuselage, the engine (sometimes in packs of two...) and the instruments, normally located in the cockpit for pilot's use.
Some would argue that the pilot itself is part of the plane. This theory will be particularly "en vogue" by certain pilots who live true relationships with their planes, but no, the pilot is not part of the plane. MM Cessna and Piper never delivered any pilot, as far as I know.
Airframes have been made of a wide variety of substances, wood, fabric, paper, aluminium, and occasionally with addition of insects or birds.
Recently however, the plastic revolution took place. Ok, some like to call it "carbon fiber", or with even more complex names, including chemical formulae. Nevertheless, when you touch such a plane, or gently hit the wing (yes, gently only), it sounds just like plastic... because it is.
Let me be very clear. Wordings like "plastic plane" or "plastic flying" may sound cheap / unsafe / risky. This is not my point at all, and this blog is precisely about my own experience of flying plastic planes.
I just call them this way because it's fun, and fun is all what flying is about.
Back now on the three components of a plane. Airframe is easy, and know you can share my concept of "plastic airframe".
Engines are more a metallic thing. But just like plastic changes the airframes, a recent change happened in light aviation engine technology: turbo-diesel and FADEC. With that kind of engine, the pilot gets rid of many possible mistakes, a.k.a. prop and mixture lever, pumps, carburator heat, and so on. So to distinguish these new engines from the classical one pilots were used to, I call them "plastic" engines.
And what about instruments ? A bit before the plastic engine revolution, instruments moved from electro-mechanical individual dials, to integrated "tv-like" panels, that manufacturers names "glass cockpits". As they are LCD panels now, the term "plastic" cockpit would be better, would'nt it ?
Any plane can then be classified depending the ammount of plastic in it, from nothing to all plastic (airframe, engine, instruments), with all possible variations.
As mentionned above, this whole blog is about flying planes with plastic components, and I wish you plastic fun while reading it.