I've got a couple of diffrent model-Aero seats that are basically moulded shells with padding on them, and I also have a R/C buggy with a similar scale seat fitted. If you knew what you wanted, might be ble to fix you up, or take measurements for you to make your own.
There are also some cockpit kits available, and a range of seat-belts, harnesses, joysticks, instruments, etc, but they might not be substantial enogh for your purpose, and they can also be a bit pricey, but it's another avenue of investigation.
With reference to (model) aircraft seats, especially those fitted to 'between the wars types', the seats aren't much more than a basic shell or bucket and similar to some of the Airboat seats, and are also relatively easy to replicate using the appropriate section of a suitably-sized/shaped plastic bottle or container, then just add the necessary framework to suit your model.
How to cut a square bottle, and/or £20 for a 'scale' Focke-Wulf FW.190 Seat?
