The Eagle looked like this in his first appearance in Science Comics. The Public Domain Super Heroes site informs us that Eagle could not fly, but he had an “anti-gravity solution he soaked his cape in.”
This is how he looked for Science Comics #2. Perhaps his shirt and pants were still at the laundry.
His own title, The Eagle #1, came out in 1941, on the heels of the success of Timely Comics’ super-hit, Captain America #1. That first issue sold so well that Timely Comics publisher Martin Goodman went back to press for more copies to keep up with the demand. That would probably be enough to get Victor Fox, publisher, to turn The Eagle into a soldier, and even include that young friend. Captain America had Bucky, The Eagle had Buddy. The Eagle’s costume was changed (again), this time with a red-striped cape for both Eagle and Buddy, reminding one of an American flag.
No writer or artist attributions by the Grand Comics Database. From The Eagle #1: