[GreenLanternCorps]

There is an exception to this rule, in time of war, when one nation scores a victory over another nation, you often fly the flag of the victor over the flag of the loser.

This is most often done when a ship of one nation captures a ship of it's enemy.

See the below link for a photo of DKM U505 after her capture by USN Task Group 22.3

[GreenLanternCorps]

Oops,

here is the link:

http://www.msichicago.org/exhibit/U505/history3.html