Becoming an Engineer with a Math degree
Note that in many places, engineering is a licensed and regulated profession. One of the requirements may well be a degree from an accredited engineering program. That depends on local laws, of course. 

The aerospace industry employs a lot of engineers, of course, but not everyone there needs to have an engineering degree. It may well be that, depending on laws and the policies of an organization, modeling of various phenomena may not require such a degree. In fact, as a guess, it may well be that engineers (licensed) may only be required in the actual design and development process. 

And, it might all be that a degree in math or statistics or CS might be a better qualification for some of the tasks required in the industry. 

However, you are in an excellent position to learn the specifics for your case just by asking someone at your current company. You can get some pretty good advice by going to the employment office and just asking for a bit of guidance. Professors in your current program are also well positioned (or should be) to answer this question in light of local laws and such.