In Avengers: Age of Ultron, in Sokovia, Ultron plans to use the city as a meteor to destroy mankind. All of the Avengers were there in their suits fighting back. Captain America had his whole outfit and shield except the helmet he wears.
So why didn't he wear his helmet during the battle? The helmet was gone once Cap came back from Korea to Avengers Tower so he can tell Tony to shut Vison down and it was gone from that point to the end. Where was it?