Hello Sunitha H,
What is aerospace engineering?

• It is the construction, design and maintenance of aircrafts, missiles, spacecrafts and weapon systems. Main focusses include fuel efficiency, flight safety, environmental impact and operating costs.
• The two fields in which you can work as an aerospace engineer are research and development, and testing and maintenance. 
• Aerospace engineers also work on finding malfunctions in the parts and investigation of air craft crashes.
• The course includes the study of Fluid Mechanics, Astro-dynamics, Statics and Dynamics (engineering mechanics), Mathematics, Electrotechnology, Control engineering, Aircraft structures, Materials science, Solid mechanics, Aeroelasticity, Avionics, Software, Risk and reliability, Noise control, Aeroacoustics, Flight test etc.

Eligibility:

• Candidates applying must have had completed their 12th grade examination with Science i.e. Physics, chemistry and mathematics.
• The candidate must appear for the JEE Main examination in order to get admissions in these colleges.

Colleges in India offering aerospace engineering:

• Indian Space and Research Organisation (ISRO), Bangalore
• Osmania University, Hyderabad
• Andhra University, Vishakhapatnam
• Punjabi University, Punjab
• IIT Bombay, Mumbai
• Indian Institute of Science (IISc), Bangalore
• IIT Madras, Chennai
• IIT Delhi, New Delhi
• IIT Kanpur
• Tata Institute of Fundamental Research (TIFR), Mumbai
• Delhi University
• IIT Kharagpur
• IIT Madras
• Indian Institute of Space Science and Technology (IIST), Trivandum
• Indian Centre for Space Physics, Kolkata
• Savtribai Phule Pune University - Department of Atmospheric and Space Science, Pune
• Cochin Institute of Science and Technology - Department of Atmospheric Sciences, Cochin
• IISER, Bhopal
• IISER, Kolkata
• IISER, Pune
• Madras Institute of Technology (MIT Madras), Chennai
• Manipal Institute of Technology (MIT Manipal), Manipal
• Indian Institute of Space Science and Technology (IIST), Thiruvananthpuram

Scope of aerospace engineering:

• Designing and manufactuing of machinery like missiles, aircrafts, air weaponry, satellites and space shuttles. Aerospace engineers have a lot of scope in designing and manufacturing of aircrafts. They are recruited both nationally and internationally in private and public sectors.
• There are multiple research opportunities which open for aerospace engineers.
• Major job opportunities for aerospace engineers are available in the airlines, air force, helicopter companies, corporate research companies, defence ministry, NASA, aviation companies, aeronautical laboratories, flying clubs, aircraft manufacturers etc.
• Certain job positions are aerospace designer checker, aircraft production manager, mechanical design engineer, assistant technical officer, thermal design engineer.
• Certain companies which provide recruitments are Hindustan Aeronautics Ltd. - HAL, Defense Research and Development Laboratories - DRDO, Indian Space Research Organization - ISRO, Civil Aviation Department, Air India, Tata Advanved Systems, Mahindra Aerospace, Taneja Aerospace, L&T, Samtel Avionics, Pawan Hans Helicopters, Aeronautical Development Agency - ADA, Aeronautical Development Establishment - ADE, National Aerospace Laboratories - NAL.

Salary:
The starting salary of an aerospace engineer ranges from INR 6 to 15 lakhs per annum. Hiwever, the more researched, experienced and learned you are the better will be your salary.
All the best!
I hope this helps!
Do revert back in case of any doubts.