Sir, will i do mtech in mechanical or aerospace engineering after btech in information technology

Dear student,
If you are confused that what to pursue in Mtech either mechanical for aerospace engineering then you should go with aerospace engineering. In India the demand of aerospace engineering is very high and it is one of trending and most demanding Branch in field of engineering.
In aerospace engineering you have to largely deal with the design, construction and maintenance of aircraft, spacecraft, missiles and weapons systems.
You have to evaluate designs to see that the products meets the basics engineering principles. In addition, you also have to create and test the models to make sure that they function according to design and follows the rules of physics.
You will get a very better placement than any of the other branches with a very good and handsome pay and making career in aerospace engineering will be a boon to your whole life.

On the other hand mechanical engineering is one of the oldest and reputed branch of engineering.
You have study, design, develop, construct, and test the mechanical devices, including tools, engines, and machines.
Also you have design power-producing machines, such as electric generators, steam and gas turbines, as well as machines, such as refrigerators and air-conditioning systems. Also you have todesign machines inside buildings, such as elevators or lifts using principle of mechanics.
You can find jobs in government as well as in private sectors and have a great job avenues in India or abroad. Also you can get a job in any field.

Both branches of engineering are very good and reputed in their own perspectives.
But still I would suggest you to go with the aerospace engineering.