First of all let me tell you that Aerospace as a department is only there in SRM Kattangaluthur campus. With considation of the rank as you mentioned, you will not face any issues while getting into aerospace department.
I was alloted in the 3 rd day of councilling process in the year of 2014. As I remember, till the third day of councilling no seats were occupied by any single individual for aerospace. So, by going through this logic, you won’t face any difficulties.
But again it depends on the choice of people who came for the councilling. As ISRO is adding feathers into its cap, this might be the considation factor for many folks in future.