So I'm flying BOS-AMS-DEL-CCU and then CCU-BOM-AMS-BOS. BOS-AMS and AMS-DEL and BOM-AMS and AMS-BOS are all on Delta, where I get to check two bags as a GM. On the way there, I'm flying Jet Airways but will Delta check the bag all the way through to CCU? However on the way back how do it get the two bags? Additionally I would have bought this through Delta, however, I had to buy through Expedia as it was the only way as Skyteam does not service CCU. Any tips?

When you drop off your bag at BOS, inquire about whether it can be checked to CCU or not. Remember that you will still need to collect your luggage at DEL in order to go through customs, even if it has been checked all the way through.

I'm more worried on the way back, when I'm not sure I'll get my bag benefit

Do you have one ticket or two? When do you fly? Delta recently changed their rules which take effect sometime next year whereby they wont through check luggage if you have a separate ticket for the connecting flight.

On the return trip the originating airline should follow the "most significant carrier" rule and give you the same luggage allowance as Delta and should check the luggage through.

It's all booked through a single itinerary on Delta, so it's all strung together. And thanks. Is my best option to just say that I'm connecting to an international flight, and here's my baggage allowance for that flight?

Your best option is to be prepared to pay the fee when you check in for the return, but be polite and courteous to the agent and see if they will waive it.

I recently checked into a flight from Hong Kong to Jakarta on Garuda. The agent checking me in was going to charge me for my second bag but a supervisor who happened to be standing nearby intervened without being asked and asked me how I had arrived in Hong Kong. I said "United" and he said "do not charge for the extra bag". Garuda and United have no relationship and the tickets were purchased separately. I was actually in Hong Kong for about 16 hours between flights so I immigrated and spent the night in the adjacent hotel before checking in at Garuda the next morning.

I'm not sure what the rules are, but I wouldn't let a checked bag fee become a big issue. How much does the whole round trip cost? How much is the bag fee if you have to pay it? Perspective.

After digging through Air India's bag policy, it states that as long as there's a continuing ticket onto Delta, they will honor their bag policy. Should I just print it out and show my GM card?