Looks doubtful to me. A provenance of being found in a crate of WWII stuff is not good enough for me. If these were genuine artefacts wouldn't you expect someone to have written (discretely on the back perhaps) the aircraft serial number and the date on it, or on an accompanying note?
They may be old, but could easily be painted canvas from a tent or something else. Especially the last one, the arms of the cross are so rough edged and uneven thicknesses - wouldn't an aircraft be marked much more accurately? Perhaps the historians on here would know more than I do about the accuracy and dimensions, instructions etc provided during WWI - however in the UK RAF there was an actual trade group nicknamed "painters and dopers" which I believe must have descended from the early days?
