Remember When Favreau Used Practical Effects For Iron Man

Well this is a video of it.



You can see whenever he moves too much that it's CGI, it'd be much more noticeable if the scene was set during the day. It still holds up but you can tell. Same with Iron Man 2 when he fights Whiplash which again was another fight scene at night. The Silver Iron Man having his test flight was at night and so on.

They may have had the practical suit in the original movie but he did spend a lot more time on the ground there, like when he fought the terrorists or blew up the tank and largely while fighting Iron Monger which they got around by him not having much energy left to fly or the different suit up scenes.

They've made him much more aerial now though and you can't exactly have a practical suit for that.