I have booked a Ticket on American Airlines for London-Chicago for a trip in March 2018, from the British Airways website (So that I would get BA miles on this booking).
American Airlines charges $100 for the second bag, and hence I need to pay this, since I'll be traveling with 2 checked in bags. The British Airways customer care says that I need to pay American Airlines directly for this excess baggage charge.
I went into the 'My Trips' section on the American Airlines, but I couldn't find where to pay this Excess Baggage Charge in Advance.
On the American Airlines Site, where can I pay for the Extra Bag in advance?