A little update.
I had zero problem to take the model in the tool box with my fire truck with me, and it made a safe trip after 13hrs flight! At the custom in Amsterdam they ask me to open the box, because they did not understand what was inside.
Some people look at it in a weird way... Some travelers while waiting the airplane ask me about my weird box, and they look at me more weird when I told them that inside I had a fire truck!
Thanks to all, above all Pete for the precious ideas...