From The Aerodrome, Section : Equipment, Tactics, Uniforms.... by Gregvan
First of all, welcome to the forum.
Identification of Flight and Squadron leader methods varied somewhat from nation to nation and squadron to squadron.
In many German Jagdstaffeln, the CO's did indeed often use streamers trailing from the wingtips, struts, elevators or rudder. These were sometimes in the German national colors of red-white-black, or Prussian black-white, or even blue and white in Bavarian units. Some Jasta CO's chose to mark their aircraft with some conspicuous display of color as well, or special markings on the wings.
In the RFC/RAF, there were rather specific patterns for streamers from the wings and tail to identify Squadron, Flight and even deputy Flight leaders, I think - but I can't tell you what they were right now. These, too, no doubt changed from unit to unit and as time went on.
In many (but certainly not all) French escadrilles that had large individual numbers painted on the fuselage (and sometimes on the wings or fin), it was often the custom for a commander to use '1'.
In American squadrons, there were regulations for a squadron CO's machine to display a large red-white-blue riband diagonally on the fuselage from cockpit to tail, and to use the individual letter "O". As expected, these rules were often disobeyed or not complied with - but there are plenty of photos of colorful USAS a/c with such markings .
I hope you don't has any objection about my "dream" Mr. Malone .
Cheers
Carlos