Germany

RWTH Aachen University, Dresden University of Technology, Technical University of Munich, University of Stuttgart are some of the well known universities for aerospace engineering.

Yes, Germany is the best place for mechanical engineers. I will suggest you to increase your percentage, maintain it around 75% and try to score over 6 band in IELTS. Also, if possible, you can learn German language. All the best.

Ruprecht-Karls-Universitt Heidelberg, Technische Universitt Mnchenand Ludwig Maximilian University of Munich, TU Berlin, Braunschweig University of Technology are Germany's top ranked universities for aeronautical engineering.

To pursue MBA, you must gain work experience of a minimum of 2 to 3 years. In addition, you must take the GMAT or GRE and IELTS. Not all MBA programs are free by the way. Visit DAAD website for more details on German education. Here is the URL
https://www.daad.de/deutschland/studienangebote/international-programs/en/?p=l&q=MBA&fos=0&fee[]=0&sortBy=1&page=2&display=list

You are eligible to apply though you will require a higher IELTS band. A 6.5 and above is required for Masters degree applicants. Visit the university websites for specific requirements though. If an university requires a 6.5 they will not consider anything below 6 considering the stringent admission procedures. If you are aiming for the TU universities consider taking the GRE. Visit the daad website for university specific information.

You need to get admission in a university, not college. Check out the link mentioned below:
https://www.daad.de/deutschland/studienangebote/international-programs/en/?p=l&q=mechanical°ree[]=2&fos=0&fee[]=0&sortBy=1&page=1&display=list

All the three are good. What is your budget?
If they offer Ph.D that shows they have tie up with industry.

It is better to search it on your own. You can use the following link for reference:
https://www.daad.de/
Most of the universities haven't changes their tuition fees to pursue MS in Germany. Thus you don't need to worry at all.
All the best.

If you want to live there and work there after your study and want to make connections then my suggestion is to learn at least German A2 level from Goethe. It will also help you to get
admission there. After you get admission, you will be offered to learn German language in your semesters without any fees.
All the best.
Note: Always opt for Goethe institute to learn German language as the embassy only recognize its certificate.