This Hawkgirl of an alternate dimension is a member of the tyranic Justice Lord in the Justice League animated series. Like her Justice League counterpart, she has a relationship with John Stewart.
Shayera and her counterpart's history were the same until Lex Luthor became president and killed Flash.
After Flash was killed, Superman went to the White House and killed Luthor. Sometime later, the Justice Lords took over the Earth and deprive people of their freedom and free speeches. At this point of time, Hawkgirl got rid of her old costume and replaced it with a new one.