IIT

Both the institutes was excellent .But I recommends according to the rank.IIT was at top and Bits ranked at 3.

Hi Dear,
IIT Bombay is the best for aerospace Engineering. Also you can go for IIT Kharagpur or Madras.

u can still apply for iiit & nit through jee main score

Hi Ankit,
The JEE main exam has already been conducted this year and the Advanced is scheduled to be held on 22 May 2016. For preparation tips, kindly refer the below link:
https://www.shiksha.com/jee-advanced-preparation-tips-exampage
https://www.shiksha.com/must-read-articles-for-jee-advanced-2016-article-12388-1
https://www.shiksha.com/10-tips-towards-your-jee-mains-advanced-preparation-article-11721-1
Hope it helps. Please feel free to revert.
Wish you luck.

Around 6-7k is enough,
But if you r about IIIT Hyderabad.they takes admission on marks!!

It depends upon your caliber and your level of comfort with self learning. If you are the kind of person who just needs a little guidance and can do wonders with it, then take the distance learning program. If you think you need constant attention, push, and someone to explain things to you, then take regular coaching. However, coaching has lesser role to play in your success than your own. Ultimately what will matter will be your practice, your understanding, confidence and stress management.

Yes, once you qualify GATE, you can join IIT for m.tech

If he thinks that he has x-factor to crack it,and he is ready for super hard work.than it will be the best decision.
But in my opinion if he is getting the nit, which is a among top 4 than he should take admission this year.
Best of luck for your son :))