Archie Comics Origin
Kim Brand, better known as Fly Girl, made her debut in The Adventures of the Fly #13, on July, 1961, where she was an actress that fell out of a hotel window, to be saved just in time by Fly Man. Subsequently after being saved by Fly Man, she fell in love with him, and wanted to be in his adventures. When Fly Man's foes, Metal-Master, and Bud Brack, wanted to outmatch him by simultaneously committing robbery and unleashing a metal-controlling alien on Earth at the same time, an emissary of the Fly People, Turan, sought Kim, and offered her a Fly Ring to which she accepted and became Fly Girl. Since then, she's constantly helped Fly Man beat up whoever wants to commit crime, be it in Earth or in outer space. Her adventures would last until the issue of The Fly Man #39, on September, 1966, due to Archie wanting to stop using hero books and instead focusing on funny comics.
She returned in The Fly #1, on May, 1983, but is reluctant at first to be Fly Girl again. She eventually joins Fly to fight crime, having to fight loan sharks who want to kill a producer for not paying his debts. She had to endure a psychopathic stalker who admired her work as actress and couldn't stand seeing her with Thomas Troy, face crooked politicians, helped a battered wife by preventing her abuse to continue, even helping both Fly and The Shield capture an impersonator who was using the costume of The Fly. Her last appearance was in The Fly #9, on October, 1984.
DC Comics Origin
Now, Fly Girl is no longer a girl who was an actress that fell in love with her rescuer. In the DC Universe continuity, she is Kim Brand, a Web Host that has scored high effectiveness rates in her web seminars. She had also modified her Web suit drastically to change her look and becomes Fly Girl. She encounters The Web when he comes to her place, asking for her help regarding the current override of the suits made by the Global Concern in order to eliminate The Cell, a group who rejected their recruitment. As soon as they arrive to where the Web hosts are converged over Colorado, one of the moles of the Concern drops a bomb on the base of The Cell, and the override sends all the Hosts to attack both Web and Fly Girl. Web and Fly Girl manage to clean up the software that gripped the suits of the hosts and avoid any further casualties, while bearing in mind that the base was destroyed. Web was quick to congratulate himself and Fly Girl for saving the hosts, but Fly Girl was quick to point out that this would've been executed better had they came with a team. That's when General Latham comes in to offer them to join a team, that when they work together, they become Mighty Crusaders.