Yeah, uhm... there's totally both a credit cookie scene AND a teaser trailer for next Summer's Avengers movie at the end of Captain America. How you could have missed that I don't know. Since you did apparently miss it, it's available on YouTube. Also, did you not pay attention to the movie? Red Skull broke off from Hitler, having only used the Reich's power and wealth to get him so far. Cap was fighting Hydra, not Hitler.