Automobile Engineering

The automobile has more scope in Germany as most automobile companies are there only.

Yes, Chandigarh University is a good University for automobile engineering, because CU provides good quality of faculty members, good course curriculum, good placements and good infrastructure also.

If you are an automobile engineer, then you do not need to take any course for experience. You have to do job or apprenticeship in auto mobile sector. No any course will give you better practical experience then job.

Yes, they provide lateral entry for B.Tech in automobile engineering. You can apply for admission.
Good luck.

Kindly predict your college in this college predictor. JEE Main rank predictor is an online tool which predicts the candidates rank range and probable colleges based on the difficulty level of the examination, average marks scored in JEE Main and seats available in IITs, NITs, GFTIs, and other SFTIs. The rank predicted might not be accurate but it certainly does give an idea to the aspirant. Know your college admission chances based on your JEE Main Rank, Home State, Caste, Gender, etc. here:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor

Yes, you can do Diploma then you can get direct entry in second year of engineering in lateral entry. Good luck.

Yes, you can do MS after mechanical engineering. It is a good option. And, you can choose automotive industry you will get good opportunities there. Good luck.

If that Diploma is equivalent to Class 12th, and you have scored 50% marks aggregate, then you can go ahead for CPL Training.
Refer to DGCA CAR for Civil Air Crew for more details. You can find it on Google.