For 6mm I use Litko flight stands, available in the US.
They do different sizes of clear base and I use either 1inch or 20mm bases, available in packs of 10 for a few dollars. They do clear pegs of varying lengths and for a tabletop battle I use 1 or 2 inch lengths. The pegs are just push inserted into the base and can be removed for storage.
To attach the plane to the stand I glue a round 3mm diameter magnet of 2mm height to the top of the flight peg. You can get these magnets from various manufacturers and they can be quite cheap.
I glue x2 3 to 4mm lengths of ferrous wire together side by side in parallel to the underside of the plane (call them gun pods if you want). When they're together they form a bit of a flat platform that can rest on the magnet.
I've got a reel of 1mm thick wire about 20m long from a gardening shop for about 3 bucks years ago (actually a few quid but I translated 😊).
The plane should then click on to the magnet on top of the flight peg.
To get the plane to bank or nose up, down etc I place a small ferrous hex nut on the magnet.
So have a look at Litko, get some magnets and with a bit of gluing you should be OK.
B