My take on Steve's Beetle in Civil War
Omg I was always like "Goodness. Why did Steve have to squish himself into this tiny car!?" Of course, tall, wide man + tiny car = tall man looks even bigger, which is helpful in preparation for a fight scene (if you want to show the audience the sheer physique of a character without having them get naked; great way to do it, honestly, because it was a different approach that totally worked (for me, at least)). But right now, it clicked and I'm thinking "yes, it totally made sense to give Steve this car."
Because, the thing is: This little Beetle, Volkswagen oldie, is a car that was built first in 1938. It was a car that the Nazi government encouraged as a car that every German could afford. It was a car for everybody, specifically built for two adults and two to three children. Steve was "built" in 1942, during the same time, with the goal to give something to everybody in the States: protection.
It is my theory that the Volkswagen Beetle was chosen very intentionally for Steve in this scene. It is a lot like him, old and a result of the war (many people gave their savings so the government could build cars, the government used the money for war armament, though, so the motor and inner device could be developed for the big machinery, like planes and tanks). The funny part is that although promised to thousands of civilians, barely any cars were given to them until much later, after the war, when the allied forces were in Germany and a British officer reopened the production plant. See the parallels to Steve? The super soldier created for the war, a special commission by the government, the first of many, but suddenly, the only one. Although they had many soldiers like him in mind, the government couldn't give them to the army.
Also, the boss of Volkswagen himself criticized the car, saying it had as many flaws as a dog had fleas, leading to many reinventions and improvements of the car after the war. It reminds me of the one scene in The First Avenger, where Colonel Phillips says "I asked for an army and all I got was you. You are not enough." That's a 4F, right there. Unfit. But they both became national icons. Steve, like the car, was frozen for a while (the car's production during the war, Steve's Captain America tour and his body, during the war too, but closer to the end, of course), but both have created war bonds and helped their country to make a step forward in development and war armament.
Additionally, I want to come back to the special instruction to fit two adults and two to three children into the car, so that the whole family could go on trips together. I believe that this Beetle represents what Steve could never have; what he lost. Just imagine him sitting in this car with Peggy and three children in the back row. Family. We see that Peggy was married and that she had children (two, if I remember correctly), so what if she had been with Steve? They would've been a family, probably, and it is historically probable that they could've had a Volkswagen Beetle, no matter if they lived in the States or in the UK. The car is a reminder of what still aches in Steve's heart. We don't know who chose the car (right? or do we?), so if Steve chose it, what if it is a representation of his dreams, of his wishes that he, like many people of his generation, has difficulties expressing?
So, now, Steve drives Bucky and Sam around, his (new) family. They meet up with the others, Clint, Wanda and Scott, the other part of his family. And even though he recognizes them as such, I believe that the car is supposed to highlight who is closest to his heart, the persons he trusts the most. (My theory is that if Natasha had been on his side, she would've been placed in the car as well.)
As last point, I want to note that there have been more versions of both Steve and the Beetle; we see Bucky and the other Winter Soldiers, who have all been treated with a version of the serum used on Steve. If we look at the Beetle successors, we can clearly see the origin of them, the original Beetle. The same goes for Steve and the other super soldiers; they are all comparable strength-wise and body-wise. Yes, I agree, the most important part, their heart and their morals are not the same, but look at the Beetle: while most of the car looks similar to the old Beetle, they changed the motor that drives the car (plus the furniture). Isn't that what Hydra did? They changed everything inside. (So, the car fits for Bucky too, to a certain degree.)
So, we see two of the greatest icons of that past era together and you wanna tell me the car had been chosen randomly and just didn't fit into the scene? I gotta say, I disagree.
There’s two articles you can visit to read up on all this stuff, one of them a nice comment on a picture and the other the regular Wikipedia article on the VW Beetle.
As said before, this is my theory. You are free to interpret the VW Beetle in whatever way you want, you are even free to say that this is all bullshit and that the car shouldn't have been in the film at all. That's alright, it's your opinion. Please do respect mine. I would love to hear your opinions, though. Have a great day, all of you sweet people :D