The Union flag, called the Stars and Stripes, symbolized team spirit and patriotism

https://ericksigh824.birchreport.com/posts/embodying-history-the-role-of-civil-war-flags-in-reenactments-3

The Union flag, is named the Stars and Stripes, symbolized solidarity and patriotism, featuring 13 stripes and a discipline of blue with stars that represented each country within the union.