Well, the point is that the cloth stripes (red ribbons) that I used to cover open tips of tubes (pitot and fuel tank breathing) simply disappeared, maybe removed by the wind. How to make them hold better?

I cut small pieces of aluminum tube, about 1 inch, and riveted them to the cloth stripes, so that these tubes stand 90 degrees to the cloth (rivets into the tube pieces). Then I pulled a small piece of plastic hose onto the tubes leaving about 1/2 inch free to be pulled onto the open aircraft tube tips. This keeps the protection clothes well on place. If we want to make some inscription (like "remove before flight" or simply the craft regsitration), DO NOT try to write with white paint (I tried, and the the result is really poor). Instead, use a photo of a drawing (done with the computer, the letters are perfect), copied onto photo paper by lab devices, then cut the ribbons as required. These ribbons can then be used instead of cloth, and they look really professional.