1

Bangalore is no longer a small airport. It has as many if not more flights than Chennai. I don't know about Ahmedabad and Amritsar.

2

The best way to check it is to look up the Wikipedia page for each of these airports. There is always a list of destinations on Wikipedia pages of airports. Then I would advise to check on the websites of the relevant airlines if the information is up to date.

3

Amritsar Airport is the smallest of the three on your list with only Air India and Qatar as the major International airlines landing there.

Ahmedabad has a few more options in terms of International flights with Qatar,Emirates,Singapore airlines and of course Air India landing at Ahmedabad.

Thanks to the Information Technology boom, Bangalore is now a major city of India and almost all Airline carriers that fly into India now also land in Bangalore including Air France, British Airways, Lufthansa, Emirates,Qatar,Singapore Airlines and of course Air India.


Bangalore International Airport in south India will provide you with the best options for flights in/out of India.

4

I cannot clearly ascertain as to what level Ahmedabad, Bangalore & Amritsar airports accept international flights.
Subject to what is allowed in or out, we will start or end our trip via one of them.

The three airports you quoted have international flights. Therefore in order to know which one(s) could be useful for you (if any) we should know what's your departure airport and where do you want to fly out.

5

I agree with #1

Bangalore is now a large airport.
FWIW I flew into BLR from Chengdu in China. There were many flights in/out that day.

6

Qatar is serving Amritsar from Doha as well as Air India from Manchester or London, don't remember. Also Turkmenistan Airlines from Ashgabat and Uzbekisten Airlines from Tashkent.