War flags

Several countries (including the United Kingdom and the former Nazi Germany) have unique flags flown by their armed forces, rather than the national flag.

Other countries' armed forces (such as those of the United States or Switzerland) use their standard national flag. The Philippines' armed forces may use their standard national flag, but during times of war the flag is turned upside down. These are also considered war flags, though the terminology only applies to the flag's military usage.
Large versions of the war flag flown on the warships of countries' navies are known as battle ensigns. In war waving a white flag indicates surrender.