Hello there! 

Greetings! 

After completing your class 12th , to be an aeronautical engineer you have to have a degree in aeronautical engineering (B.E. or B.Tech). It is a four-year full time degree course. You can go for jee exam to get into good colleges for aeronautical engineering. 

One can further study to get a master's degree in Aeronautical Engineering as well.

Thankyou