The planes all have small metal posts of what I think is brass wire. This is inserted into airplane servo arms (ball joints) which are stiff enough to all you to tilt the planes for cinematic effect during the game. The joints on the bottom end have the stiff wire which is of sufficient size to nest quite snugly into brass rod....the heart of the system.
The rods come in 6 lengths, and each one has a tiny number scrawled on them. The numbers are a bit worn from use, but you can usually figure it out by looking at the pile. Each length of rod corresponds to one of the altitude bands in the rules.
The rods then fit quite nicely onto the bases, which also have some of the stiff wire. The wire also acts as a pivot for a dial to indicate air speed. Possibly one of the greatest things about this system is that it breaks down to a very small size, and there is minimal prep work for each plane to make it compatible with the mounting.
The first pic is a good shot of the upper assembly. You can see one of the downed planes lying on the mat with the servo ball joint thingy.
The second shot gives a good sense of the height differences. The Italian planes have all just some step climb and turns as they come past the bombers to try and get on their tails. The Italian plane to the right closest to the picture (not one of the british fighters in the foreground) is a bit loose in the brass rod, but it does give a sense of the fight of the brass stem into the rod.
All the pics are fairly high resolution and can be clicked on for a closer look.