And I have FLAG knowledge
The Big Bang Theory Season 5, Episode 14
Perhaps even a red FLAG,
and speaking of red FLAGs,
The Big Bang Theory Season 9, Episode 15
Than to fly a pennant
FLAG or banner
The Big Bang Theory Season 10, Episode 7
White FLAG!
Money Heist Season 3, Episode 5
about how Haiti and Liechtenstein
discovered they had the same FLAG.
The Big Bang Theory Season 10, Episode 21