Planes, like quadcopters, are as complicated or simple as you want them to be. They're available fully ready to fly, as kits with different levels of work needed, or you can build from scratch and choose your own parts and design.
Flying is pretty different, though. If you're used to a copter that will just stay put when you release the controls, flying planes will be an adjustment.
Yes yes! Flying an aeroplane has no pause button. You are on your own from taking off to landing. It's a great practice not to panic under stress (I never flew one but I guess racing FPV quadcopters probably has the same feeling)
Flying is pretty different, though. If you're used to a copter that will just stay put when you release the controls, flying planes will be an adjustment.