In army contexts, flying flags serve as very important symbols of honor and sacrifice

https://tysonudwh118.cavandoragh.org/flying-the-american-flag-what-it-represents-and-why-it-matters

In army contexts, flying flags function good symbols of honor and sacrifice. They are raised for the duration of ceremonies to keep in mind fallen soldiers, reminding us of the worth paid for freedom and the values that unite nations.