Though originally conceived as a mere sidekick/love interest for JSA Chairman Hawkman, Hawkgirl grew to be a mighty warrior through decades of battles. According to Wikipedia:

"Hawkgirl owes her powers to a belt of Nth metal, a substance native to the planet Thanagar (once home of another pair of Hawk-heroes, Katar Hol and Hawkwoman). The metal is psycho-reactive, responding to its bearer's thoughts and in its base form has a number of electromagnetic/gravitational properties. To the Hawks, it grants the power of flight, superhuman strength, super-acute vision, and an enhanced healing/regeneration ability."

"Additionally, she displays advanced hand-to-hand combat skills. Like Hawkman, she retains the knowledge of several lifetimes worth of fighting. Her preferred weapons are a spear or mace, but she has also been depicted using swords, axes, warhammers, shields, and other melee weapons."

"In addition, the nth metal knife which murdered Hawkgirl in her original incarnation as Chay-Ara had an unusual effect upon her soul and that of her lover Khufu (Hawkman). The pair are locked in a seemingly endless cycle of death and rebirth throughout the centuries. While not a superhuman power per se, this propensity for reincarnation has allowed Hawkgirl to cheat death and return to active duty in her current incarnation."