Aeronautical - engineering is a prestigious branch and it prepares the aspirants with all the valuable inputs related to that streams in the colleges mentioned below-
1) Amrita Institute of Technology and Science - Tamilnadu.
2) IIT Chennai.
3) Lovely Professional University.
4) Manipal Institute of Technology, Karnataka.
5) Nationa Institute of Technology, Calicut.
6) Nehru College of Aeoronautical & Applied Science, Coimbatore.
Since you are interested to persue in South India, I did not mention BIITS Pilani, IIT Delhi, IIT Mumbai etc for your perusal in the same stream.
You have to fill up the application - form of the Institutes as stated above and you have to qualify the written and oral tests of these institutes. IIT chennai is a reputed Institute and to secure admission in this Institute, you have to qualify both IIT main and IIT advanced. You may make an attempt for this Institute for your bright prospects in your service - career.