Dear Suraj, if you are interested in the designing bikes and cars then the most suited course for you is Automotive Designer.

Automotive designers create concepts using sketches and computer-aided design (CAD) programs for the visual appearance, as well as functional performance, of vehicles. Automotive designers spend the majority of their time working in an office but may occasionally work on production floors where their designs are produced. Like for all other industrial and commercial designers, a bachelor's degree is the most common path to employment.

All the best. 

Feel free to ask for any query.