Mechanical Engineering

Hi Aditya,
You can start your career by learning different software. The mechanical design engineers have to learn different software, because not every company uses the same software for CAD, CAM or CAE. There are many software that can be helpful to find jobs for mechanical design engineers like:
1. Autocad - this is a basic and must learn software, AutoCAD draughtsman jobs are plenty in the market. 2. Solidworks - The best 3D modelling software, very useful and dynamic. Jobs opportunities are very high
3. Catia - Most complex software, useful where there needs to be precise surface finishing such as in aerospace engineering or creating aerodynamic / aerofoil structures
4. Solidedge - Used in Medium scale industries, biomedical tools manufacturing, Lifts manufacturing industries. This software is a product of Seimens and works very efficiently.
5. Inventor / Fusion 360 - This software are generally used at the institutional level, The inventor Professor are paid a high salary at institutes. The Fusion 360 helps you learn CAD, CAM and CAE at one place.
6. Seimens Nx - Formerly known as Nxcad or Ugnx, a great product of Seimens used at medium scale or small scale industries.
7. Creo - Highly Agile, assembly properties and Analysis is very advance. This is all in one package for modelling, creo is difficult to learn but once you learn it; you will find ease in learning other software. Very high in demand nowadays. Start your career with Internship, so they will teach you all the basics of designing and detailing. In this way, you will work independently when it comes at the industrial job.

This is a tough question. But you should know that both the fields have different end goals for a student, but can overlap in certain situations. Mechanical Engineering is a core branch and has been a favourite of students who wish to get into the aerospace and aeronautical industry. The reason is that it gives you a broader knowledge in the mechanical domain, which includes the aerospace domain as well. Another reason is that organizations in India, whether Public or Private, prefer mechanical engineers for their broad spectrum of knowledge. Aerospace engineering focuses more on the aerospace and aeronautics industry and is an apt course for people who wish to mostly work in the private sector. It can also pave the way for a higher education abroad and then opportunities to work in international organizations (such as NASA, Airbus, Boeing, etc.).
You can go for aeronautical engineering as it is more specialised.