Dear aspirant,

Yes, you can study Pilot after completion of B.Tech Civil Engineering. You can become Civil Aviation Piolet but might not Fighter Piolet because till the time you complete B.Tech Civil Engineering and join Piolet course you'll exceed the age limit for Fighter Piolet. There is good scope for Piolet and most of them are opting for it after graduation.

Hope this information helped you.

Good Luck!!