A nice simple method is to use a "Rolson" inspection mirror ( really cheap on Ebay) and a large base.
Take the screw out of the end ( you will need this later)

Take the mirror off and file the "ball" to get a flat surface. Glue a magnet to it.

Make a hole dead centre of the stand and weight the bottom with some washers.

The finished stand.

Find the centre of gravity for the plane model a either recess another magnet or a ball-bearing.

Cheap, simple and pretty robust.
Regards
PM