India

For that, you have to apply for the UTU counselling from that only you would be able to get admission in this college or through the spot round of the counselling.

Yes, you can, but for that, you need to score very good marks in JEE Mains only then you would be able to get admission in this college.

You can do BA in Economics. Good colleges are Loyola College-Chennai, St. Xavier's College-Mumbai, Christ University-Bangalore, DU, JNU, University of Hyderabad, Calcutta University, University of Madras, University of Lucknow, etc.

Yes, you can get admission in Karnataka or another state through lateral entry.

You can buy the model question papers from Makhtaba in JMI and can study any basic book which is based on geography. You can buy MA Geography entrance book of DU.

Every branch has it's own value. Although, India is developing country, so aerospace has a lots of scope. There are too many jobs in PSUs related to aviation field. All the best.

Your profile is very good. You will require following things to apply an American university for undergraduate degree:
1) SAT, SAT subject test and TOEFL score
2) Two teacher's recommendation
3) One counselor recommendation
4) Your 9-12 grade marks
5) Your personal essay
6) Extracurricular activities which you have already mentioned. Feel free to ask questions.

Yes, you are eligible for the course.