Fred has asked a question on the flight stands I use for 1:300 aircraft here are a couple of photos. The tall one I use for FoW hence the little stone counters on the base, it is weighted with a big washer as it obviously normally takes a larger plane.
The other stand is the type I use for air combat games, Games Workshop Aeronautica bases but with a longer stem. Which is 3 or 4 mm plastic rod. The photo of the planes shows some evolution I had the grand idea of sinking the magnets into the planes but realised this was a faff getting the plane level and you never really see the underside anyway. The Stuka has the magnet just stuck on the base which is easier to fix and just as effective.
I have tried to show the detail of the nail head stuck to the top of the rod. I clip most of the pointy bit of the nail off and then drill a small hole. The trick is to get it as level as possible. Hope this helps.