What's the difference between "flag" and "banner"?
Native speaker’s answer
Rebecca
"Flags" are attached at one end by a pole while a "banner" is generally attached at both ends or mounted onto something. In this case, however, the word "banner" refers to the flags that they are holding, but it is also used as a symbol to mean their army or their people. Having their "banner" or "flag" advance symbolizes them winning the revolution.