In WWII everyone who had a son or daughter in the service displayed a Service Flag in the window.
It is now re-authorized by Congress and available again.
The flag (8 1/2 by 14) is an oblong with a two inch red border around a white field. The center has a blue star on the white field, one for each son or daughter in the Armed Forces. It is supported on a dowel and there is a gold braid with which to hang it in a window.
If the child died a gold star was sewn over the blue star leaving a small border of the blue around the gold star. Hence the term "Gold Star Mother."
If you have a child in Armed Forces and would like to display a Service Flag - I was given this number where they may be obtained : 1-888-453-4466
Ask for the "window flag" or you might get quoted the price of a huge display flag.
Sorry I haven't prices but I received my flag as a gift.