US Army soldier: Wait! You know what you're doing?
Steve Rogers: Yeah, I've knocked out Adolf Hitler over 200 times.
When the action moves to England after the failed award ceremony, the British Union Flag hanging from the wall is upside down. The broad white band should be at the top left (nearest the top of the flag pole).
At the World Expo there is a display with a mannequinn in a red suit inside a glass tube, a reference to the original Human Torch Jim Hammond who fought along side Captain America in the comics.