Eles queriam fugir do Aquaman e usar o Hawkman, mas não estavam satisfeitos com uma formação que incluía apenas uma mulher (Mulher Maravilha), então decidiram usar o Hawkgirl baseado na versão da Era de Prata conhecida como Shayera Hol.
Do artigo Wikipedia :
This new animated TV series brought all sorts of new characters. Ignoring the sidekicks, pets, and other elements of the earlier Super Friends show, the line-up of this new JLA adaptation was created with two things in mind: to pay tribute to the original line-up of the Justice League of America while also reflecting racial and cultural diversity. Significantly, the well-known superhero Aquaman was left out of the lineup (although he would become a member of the team on Justice League Unlimited), and was replaced by Hawkgirl, the team's second female (along with Wonder Woman).
E no artigo Hawkgirl :
Her personality was completely redesigned for the series by the producers, who wanted a second woman for the team (taking Aquaman's place) to contrast with Wonder Woman. While Black Canary is traditionally more associated with the Justice League, the producers preferred to have the Hawk family represented.