Free World War II are viewable on Internet Film Archives, including films made during World War II, such as "Gung Ho!" "Dawn Express," "Submarine Base" and "Minesweeper." They are free because they are listed in the public domain, meaning their copyrights have expired.
One of the most critically acclaimed WWII film in the public domain is the 1950 film "Three Came Home." Rated 7.4 on IMDB as of 2016, it tells the true story of a American woman named Agnes Newton Keith, who spent the war in a brutal Japanese prisoner of war camp. The film stars Claudette Colbert and Patric Knowles, and it is posted on YouTube as of January 2016.