Captain America: The First Avenger was one of the few superhero origin films to not fall into the pile of origins that felt overdone. That could be for several reasons, including a stellar cast and a near-perfect recreation of the 1940s with a Marvel flair. But aside from Captain America, there was also something else that Marvel Cinematic Universe fans were ready to see on the big screen -- the iconic shield in action. And while Steve Rogers eventually got his hands on it, it wasn't without some hesitation by Howard Stark. But why didn't Howard want Steve to use the shield at first?
In The First Avenger, Steve was shown various full-body shields with multiple uses, from electrical relays to projectiles. But even though he had many to choose from, he ultimately went with the simple one made of vibranium. While he quickly gravitated to it, Howard was hesitant as it was the only vibranium believed to be on Earth at the time. Additionally, it was still in the prototype phase, implying that anything could've gone wrong.
Howard, like his son, was a futurist who always looked to the stars and hoped that science could be the answer to the world's problems. Considering how hard it can be to manipulate vibranium into a cylinder, it made sense why Howard wasn't willing to throw it away so quickly. There were still many studies needed before the shield was even ready for combat, and the full capabilities of the metal were still unknown.
And aside from the shield's applications, it also left Steve far more exposed than the other shields. While Stark's had defensive and offensive capabilities, it also meant that his friend wouldn't get gravely wounded in battle. Plus, he knew how much they could take before being destroyed. Finally, there was also the potential hope that this technology could've pushed Stark Industries to new heights much earlier as Howard spent most of his life searching for a renewable energy source.
The risks outweighed the dangers when it came to letting Steve walk off with an untested and rare metal, which is why Howard wasn't on board with the idea. But it was obvious that Steve was more than adept at handling it, and the shield in itself has since become iconic even without Rogers attached to it. It's unclear if Howard saw this potential as well or if Steve deflecting bullets with it eased his conscience, but it's clear he quickly understood it was in the right hands.
Howard Stark made a big sacrifice in letting Steve use the shield before it could get tested. In fact, it likely hindered his company and limited his understanding of vibranium. But as a futurist, he understood that the world would need a symbol like Captain America, meaning the shield was in the perfect hands.