click to enlarge
enlarge image
Man in Service flag
Man in Service flag

Also called Blue Star flag.
Blue star on white rectangular field within red border.
The man in service flag "may be displayed in the window of the place of residence of persons who are members of the immediate family of a person serving in the armed forces of the United States during the current war."
War Department circular, 1943

The origin of the flag, patented by Robert L. Quessier in 1917, is explained:
"Shortly after April 6, 1917, when war with Germany was declared, the thought came to me that both of my sons, who were still officers in the guard, would again be called out, and I wondered if I could not evolve some sign or symbol by which it might be known that they were away in their country's service, and one which would be to their mother a visible sign of the sacrifice her sons were making. The inspiration of the service flag came to me in that manner.'
Robert L. Quessier, in The Official Bulletin, Saturday, May 25, 1918

The War Department issued regulations on the display of the service flag in 1943, including a reference to display of the service flag following the death of a family member in service:
"If the individual symbolized is killed or dies while serving, from causes other than dishonorable, the star (or stars) representing that individual will have superimposed thereon a gold star of smaller size so that the blue forms a border."
War Department circular, 1943
Courtesy of Department of Defense