Mechanical Engineering

Both aeronautical and mechanical engineering are excellent branches of engineering. Mechanical is an ever green branch for last 50 years with wide scope in all type of manufacturing & services industries and will continue to remain same in next 50 years. Aeronautical engineering is niche branch of engineering with relatively lesser scope in comparison to Mechanical engineering. However, Aeronautical engineering has more opportunities for R&D, innovation and scope to work on cutting edge technologies. You may chose of the any based on your interests to excel in your engineering career.

1. Chief engineer.
2. Assistant engineer.
3. Designing engineer.
4. Robots engineer.

I am not quite sure, but I think most graduate programs in Germany are offered in English. And, if the medium is English, you need not require test for German.

Before going for your visa interview, you have to take the decision regarding your study program either MS or PGDM. You can pursue both simultaneously.
All the best.

Yes, you can definitely choose M.Des. after doing B.Tech in mechanical engineering. You can either go for industrial or transportation design, both are equally good in terms of placement and are relevant according to your degree.
There are only two colleges that have M.Des. in transport design:
1. MITID, Pune
2. UPES, Dehradun
Top colleges for M.Des. in industrial design are:
1. Lady Sri Ram College, DU Delhi
2. NIT, Bhubaneshwar
3. NIFT's
4. IIT, Roorkie
5. UPES, Dehradun

Below mentioned is the list of universities for mechanical engineering in Germany:
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 es.html

After completing your Diploma in mechanical engineering, you can opt for CADD as it is the best course. Either you can opt for:
1. Marine.
2. Biomechanics.
3. Piping and
4. Aeronautical engineering.