The questions asked in an aerospace engineering MS interview at IIT Madras and IISc Bengaluru will likely focus on your understanding of the core concepts in aerospace engineering, as well as your research experience and interests. My friend shared his interview experience in the same and was asked questions related to 

• SOM Vibration Plasticity
• Conditions for plane stress and plane strain
• Hooks law for epsilon x,y,z and similarly gamma xy,yz,xz.
• Poisson's ratio and range 
• A cantilever beam (Illustration)
• Maximum bending stress and its variation across cross-section (and some more technical stuff)
• Theories of failure and their development over the years
• Role of Material

Lastly, they asked if there was a specific topic he wanted to work on in MS. He was asked to exit and fortunately, he got selected.