Help me relive my youth - French/Belgian comic sought?

Many, many years ago, when I was very small I got my hands on a couple of comic books. They were by either a Belgian or French illustrator and were about a group of airforce/army personnel who came into contact with something that made them, and their equipment very small. My memory might be a bit faulty, but I seem to recall them setting up home inside a tree trunk.

I loved the books so much that I wore them out. I've since searched thoroughly, but haven't been able to find a thing out about them. The books were written in the 1970s, and the aircraft used in it were French, either Mirages or Super Etendards. Can anyone help?