In an inter­view with MTV, Chris Evans spoke a bit about his suit and shield, we don’t see his final Cap­tain Amer­ica suit until the end of the movie, and sim­i­larly, the shield keeps get­ting updated:

“But [the suit]‘s not bad. It’s a World War II movie, so I think a lit­tle bit of a cum­ber­some feel to it and some­thing that’s a bit chunkier … not only serves the time period, I think it looks bet­ter. […] It’s not this sleek span­dex suit. It looks like some­thing you might wear in the ‘40s in the mid­dle of a war.”

“There’s a cou­ple stages and ini­tially in the script, Steve isn’t Cap­tain Amer­ica right away. […] He gets the injec­tion and isn’t asked to go to war right off the bat. He’s used in dif­fer­ent areas, so he has dif­fer­ent stages of the suit. I don’t think he actu­ally jumps into the final suit until the third act of the film.”

[talk­ing about the shield]

“Well, dur­ing the USO tour, there’s obvi­ously a dif­fer­ent shield. […] And he goes on a cou­ple mis­sions, he goes AWOL and kind of takes the USO shield. And he’s kind of allowed to be this sol­dier and they out­fit him with the new uni­form. They decide to out­fit him with an updated shield.“