Not necessarily just computer science, you can choose specializations in Aerospace, Aeronautical, Mechanical, Automobile, Chemical, Naval Architecture, Electrical, Electronics, Metallurgy & Material Science, Instrumentation, Mechatronics.

To become a aeronautical engineer you will have to do btech in the above specialization mentioned(either one) and for that you will be required to appear for entrances like Jee Main, BITSAT, Jee Advanced etc. Admission to master’s courses like M.E./M.Tech will be done on the basis of GATE examination.

You can check the details about admission and further information in the link provided below:

Aeronautical engineering- All about!

Good Luck.