You will have to follow the route for Admissions as prescribed in different colleges. There are few ways you can get information. In India, each state has a state and a regional college. Then there are private colleges.

Yes, you are right that this field has limited scope. It will all depend on how good you are and also how lucky you can be to get a good job.

There are books that are available in Delhi that give names of colleges and addresses. I am sure today the Net is a useful search place. Look for REC. For example, REC SURAT, or REC Waranal and so on. Then see if they offer aeronautical engineering course.

Your counsel.