MBA/PGDM

For MBA, as it is a Masters degree you should have the under graduate degree as eligibility for MBA. You can check on internet if there is any university having some lateral entry or some other norms for Diploma holders to go for Masters.
Good luck.

NMIMS is a very reputed MBA college. Apart from the basic eligibility requirements like graduation, it has its own entrance exam named NMAT for GD/PI call.

There are many good B-Schools offering MBA. IIMs are the best to pursue MBA.
You can check the below mentioned link for some other B-schools:
https://www.shiksha.com/mba/ranking/top-executive-mba-colleges-india/18-2-0-0-0

If you are comparing salaries, ME will have lower starting salary as compared to MBA, but future prospective are very good in ME as there are fewer people in technical specialization in most of the fields.
More the experience in technical field more will be your demand and more is the salary. MBA wi

Yes, you can because the Maharashtra MBA entrance exam's course will more or less be covered in what you will learn for your CAT exam.

It entirely depends on your interest, if down the line you see yourself at a managerial position and you think you are more inclined and more interested in studying management, you should go for MBA.
But, if you feel you are more interested in learning the technicalities and want to improve your tech

NIBM is a better option for MBA.

Dear Chirag Nagda,
You can try for:
1) TISS – Bombay.
2) IIM – Kolkata.
3) Xavier Institute.
4) Symbiosis.
5) MDI – Gurgaon.
6) You can prefer IBS too.
All the best.

Dear Skanda,
MBA aviation is a very narrow field. The jobs opportunities are quite less. Therefore, you can prefer any other specialization.
All the best.

Dear Animesh,
You need to choose an institution. You should know the admission procedure after you select an institution.
All the best.