Military Personnel Free Frank

WWI sailor's mail free frank on Red Cross postal card
WORLD WAR I FREE FRANK. The American Red Cross provided free frank cards so that soldiers could assure their families that they had crossed the Atlantic safely.
WWI Officer's Mail Free Frank cover
CENSORED MILITARY MAIL, 1918. Prior to WW II, mail was franked as either officer's mail or soldier's mail. This cover has an Army Postal Service cancel and a censor mark.
WWII German POW free mail post card
WORLD WAR II PRISONER OF WAR FREE FRANK. Prisoners of war were allowed free mailing privileges. A German prisoner held at Opelika, Alabama, sent this card in 1943.