Speaking on $pay$, most aerospace jobs are middle to high earning potential (for engineering) depending on where you live/work and what you focus on career-wise. AE jobs in California pay great, but the cost of living is ridiculous while AE jobs in GA pay O.K. but the cost of living is pretty fair.
The single biggest issue that I can foresee is a shrinking job market for this role. I may be wrong but my impression is that these jobs aren't that common. HOWEVER, you will learn a lot of knowledge and valuable skills in pursuing such a degree that will help you get other positions. AND if you have a passion for this area of study then you should definitely do it - there's no better work than that which you're interested in.