Aeronautical Engineering

Both degrees are equally good. Aerospace is a specialisation in Aeronautical Engineering. You can chose either without any fear or concerns.

I don't think that you'll get Aeronautical Engineering at 70 marks. I suggest you go for a 2nd attempt and get atleast 100.

HelloThere are many top aeronautical colleges in india. You can get admission in these colleges through JEE(main+ advance) exam.You should hard study for this.
Eligibility for Jee, the candidate should be 12th passed in PCM with 75%.
For more information about these colleges visit this link
https://www.shiksha.com/top-aeronautical-engineering-colleges-in-india-rankingpage-49-2-0-0-0
hope this helps you.
Thanks
best of luck

Indian Institute Of Aeronautical Engineering & Technology
Gujrat Institute Of Aeronautical & Telecommunication Engineering
Gujarat Technological University - Ahmedabad, Gujarat
Ahmedabad Institute Of Aeronautical Engineering And Information Technology - Ahmedabad, Gujarat
Sardar Vallabhbhai Patel Institute of Technology (S.V.I.T.) - Valsad, Gujarat
Western India Institute Of Aeronautics - Ahmedabad, Gujarat
School of Aeronautics, Dwaraka( Gujarat )

Hi
Check this link on https://shiksha.com
https://googleweblight.com/?lite_url=https://engineering.shiksha.com/aircraft-maintenance-engineering-colleges-in-tamil-nadu-categorypage-2-61-1-0-0-1-123-2-0-none-1-0&ei=N0y0E3Il&lc=en-IN&s=1&m=716&host=www.google.co.in&ts=1461078427&sig=APY536xUflA-Qb1ow_Ckp37j0CQKGz_FjA

Once you have cleared Diploma with 80% marks, one arrear should not be problematic for lateral entry into BTech Aeronautical Engineering.

Of course you are fit for job.
You may search around Job portals as I can see so many recruitments are going on.

srm,Iit,nit,srm

If you consider studying in Canada you don't need this score. Moreover aeronautical is a popular choice in Canada. I could have suggested usa however if you wish to consider this year admission, you are already late

both are equally important, depends upon your area of interest,