A lot of undergrads, in particular freshman are not aware, that you can pretty much get into any engineering/science related field, if you have a strong curriculum in mathematics and physics. If you go and talk to employers, certainly some will be predisposed to hiring mechanical or aerospace engineers, but you will probably also find that many people working in aerospace are math majors, electrical engineers, or physicists.
The fact of the matter, is that a degree in aerospace is not a guarantee that you'll work for an aerospace company. A degree in mechanical does not mean that you can't work for an aerospace company. Most companies are looking for bright people who are dedicated and motivated. Get some work experience, when you are starting out your career early, and you can almost certainly get into whatever field you want (provided your major is at least somewhat related).
Picking your major != deciding the rest of your life. You can always get an advanced degree in another subject, as long as you are strong in math and physics. I would almost universally recommend math or physics as an undergrad degree, because they are so broad.
However, my largest piece of advice. Find something that you have a passion for, and find a way to do it. It makes life, much, much easier.