I don't do engineering but I have a lot of good friends who are. I can't imagine making such a significant decision about your future so early in your career! In my law degree I get to study a broad array of subjects through out my whole degree while all my engi friends are choosing their fields already!
It sounds like you're trying to decide between doing something you are really going to enjoy but with less job certainty and something you might not enjoy but with greater job certainty. For me this is a no brainer really. Do aerospace. This choice you are making is maybe going to dictate what you do for a long time to come, it's better that you do something you love than soemthing you don't.