M.Tech

If you feel you can contribute further to the growing world of technology after the completion of an M.Tech, M.Tech may be preferred. If you are confident of your skills as a manager, wish to jump to some middle or higher management level and the aim to climb the corporate ladder then MBA is not a bad choice.

Both are good options, if done from a good institute. You may also have to do a job in banking sector or real estate sector. You may never know where you may get placed from college. But, nevertheless MBA is a pretty good option after engineering, if you want to have a good career opportunities as well as quick growth.

Check out the links for details :
https://engineering.shiksha.com/me-mtech-in-mechanical-engineering-in-bangalore-categorypage-2-59-587-0-0-278-106-2-0-none-1-0#cateSearchBlock

University of Toronto, University of Alberta, University of Waterloo, McGill University could be the best options. Visit the university websites for admission requirements. These are competitive universities.

Hello, Both are the best field.
Here I am providing you the experience of one person
https://www.quora.com/Is-it-a-good-decision-to-go-for-an-MTech-after-a-MSc-If-so-what-are-the-scopes-available-both-in-India-and-abroad

No, combined B.Tech + M.Tech is equally valued as compared to separate B.Tech and M.Tech.

Yes, you can definitely join Indian air force after completing degree in mechanical engineering. Top colleges of aeronautical engineering in India are:
1. Indian Institute of Aeronautical Engineering, Dehradun
2. Indian Institute of Space Science and Technology, Thiruvananthapuram
3. PEC University of Technology, Chandigarh
4. Sathyabama University, Chennai
5. UPES, Dehradun

Yes, America is a good option to pursue aeronautical engineering but you should not rule out the option of studying from India as well. India is a growing country in this field and people are getting very good pay as well. I can list down a few colleges I know of in India:
• Indian Institute of Aeronautical Engineering, Dehradun
• Indian Institute of Space Science and Technology, Thiruvananthapuram
• PEC University of Technology, Chandigarh
• Sathyabama University, Chennai
• UPES, Dehradun

Aeronautical engineering is more of a specialized stream where you will limit your job opportunities to the respective segment of industry. Thermal Engineering, Nano Technology, Fluid Mechanics, Industrial Engineering etc. are also in demand. But if you aim to push yourself into the academic stream, then any post graduation will do.

Even with a B.Tech, you can put yourself into the military track.