Wikipedia says:
"Yankee Girl: This character originally debuted in Harry "A" Chesler's Punch Comics #1 (1941), in her secret identity of Kitty Kelly, an air hostess. She then appeared in the Yankee Girl costume in Captain Flight Comics #8, now with the ability to gain great strength in time of crisis."

I've never been able to get a copy of Punch #1 to read it, so I'll just have to take Wikipedia's Word for this. However a puzzle exists: Kitty Kelly has super powers too, and her super-heroine costume is similar, yet different from Yankee Girl's -- a red mini-skirt and blouse with a blue cape (not all that different from Yankee Girl's costume, except Yankee Girl's suit has red and white stripes (like the Flag) and her cape is blue with white stars all over it (like the Flag). Also Kitty Kelly's Costume has 2 large letters around her neck -- they are not YG for Yankee Girl, but KK for Kitty Kelly. If Yankee Girl's alter ego is Kitty Kelly in Punch Comics #1, why does Kitty Kelly have her own costume and superpowers in Red Seal Comics #17. Go figure. The good news is: she's very sexy looking, and subject to many perils despite her super powers of mystical origin. In this issue of Red Seal, Kitty uncovers a plot by a shady meat vendor named Nick Nicotine who switches bad meat for good meat, then sells it to a local nursery school, causing the children in the school to come down with ptomaine poisoning. Kitty Kelly investigates but is quickly spotted, hand gagged, and tossed into a meat cooler to chill out. She changes to her super alter-ego, busts down the door of the freezer and whips up on the baddies. She then changes to her "street clothes" ... note the undressing scene I enlarged below -- are those her panties we see as she undresses? (remember, her mini skirt is red, not white!! -- good show, Chesler, good show!!). It's not clear to me when she has super powers and when she does not, but in her "street clothes" she is picked up at gun point, put into the baddies car, hit in the head with a pistol, knocked out, and arm carried to their hideout. She promptly wakes up, escapes, and apprehends the child poisoners. I particularly am impressed with the splash page to this story showing her lifted up by one hand and held helpless by one of Nick Nicotine's thugs while two others rush at her with lethal weapons. Would have loved to see this scene played out in the story but it was not. Too bad. I had a lot of fun reading this one. Hope you do too.
Source: GACD