Hello Aspirant ,

You cannot get M.tech admission in Aerospace engineering in Indian Institute of Technology after completing B.tech in computer science .

According 2020-21 admissions IIT , Bombay aerospace engineering is divided in four category

• Aerodynamics (AE1).
• Dynamics & Control (AE2).
• Aerospace Propulsion (AE3).
• Aerospace Structures (AE4).

Above four categories Civil , Mechanical , Electronics , Instrumentation engineering eligible they cannot mention any where about computer science.

Different institute have different rules So,may be some institute or state colleges allows for M.tech in aerospace after B.tech cse and i am providing colleges list for M.tech in aerospace engineering in India go through it for more idea.

https://engineering.careers360.com/colleges/list-of-me-mtech-in-aerospace-engineering-colleges-in-india

I think this answer will help you lot

All the best!!!