Paul, I presume you are on vacation as I have had no response to the strap line Gene used on his bass drum from Nov 1941.The U.S.A entered World War 2 Dec 7 1941, and this strap line was the endoresment and official song of the U. S. Army Air Corps.
Jan 31 1942 is the earliest original advert I have from Billboard magazine, which is a half page and is very nice with a great photo of Gene( Maurice Seymour) on the right hand side. On the left is the logo" LET'S GO! U.S.A. KEEP 'EM FLYING " complete with the three fighter planes and several other references to this official song and then general material all Gene related.
Look forward to hearing from you soon.