The first appearance of Hawkgirl is when she appeared in a dream of archeologist, Carter Hall. He met her the next day and they became a couple. Hawkgirl first started wearing Hawkman's wings in order to confuse his enemies. After a while, she would join the Justice League.
Justice League Heroes.
When you unlock Hawkgirl by getting 70 shields, she is a mixture of another character. She has a sonic scream like the hero Black Canary