Aeronautical Engineering

The scope of aerospace engineering depends on which area you want to specialse in. Like as follows:
HAL (Mostly Aircraft Structures)
NAL (Aerodynamics and Materials)
ISRO- Well ISRO does not have a separate recruitment for Aerospace engineers, you'll have to look into materials, electronics, and structures.
And there are private companies like GE, Honeywell, etc.
Although my suggestion would be to never settle just after Bachelors in aerospace, this is a very vast stream and Masters is kind of mandatory. A Bachelors pay scale may range between Rs. 20,000-45,000 per month. However, a Masters can actually increase the pay by about 3 times.
SPOILER ALERT: The one thing that you would need to excel during your Bachelors is mathematics! I cannot stress this enough, but every subject is a derivative of mathematics. You need to be good-very good at calculus and numerical methods. So please do not take the introductory courses lightly in your first year.
Aerospace engineering requires knowledge about almost all the other branches, be it electrical, mechanical, civil, computers, everything. The scope is really wide because after graduation you can get into any of the fields.