I believe one can carry tripods on carry-on bags. But its advisable to fit that inside the luggage than strapped to backpack/camera bag. I've carried my tripod like this on two occasions.
First time I traveled on Jet Airways - a domestic flight between Bangalore and Delhi. I packed that in a kit (one similar to sports bag) and a friend who was travelling with me packed his tripod in his rucksack. We were allowed to to carry them.
Second time was on an international flight - Emirates (from London to Bangalore via Dubai). This time the tripod was in a hard case carry on bag. And there was no problem carrying it.
Jet Airways, Kingfisher and Air India being Indian airline operators - they have almost similar guidelines. So carrying a tripod on these might not be an issue.
EDIT by OP:
- Aeroflot allows tripods on their planes but I wasn't able to bring it not because of their rules but because of security check in Zagreb airport.
- Kingfisher Airlines does NOT allow tripods on any of their flights nor does Go Air.
- Air India allows tripods on all their flights except the ones to and from Leh, Jammu and Srinagar.