I had two tickets with AA that were separate but two thirds of a single trip. One was to fly from SFO to MCO and the second (actually the second half of a ticket purchased via BA) to fly home from MCO a week later via MUC. The CLT-MUC flight had been cancelled fairly early on--a day or two before my flight from SFO to MCO. When I got to the airport, I asked AA if they could re-route me back to Europe that day and refund my flight from SFO to MCO. The check-in agent made several phone calls and found me flights home at no additional charge and offered me a voucher for the SFO-MCO flight. Great service and attitude. When I went over to BA, they couldn't see the ticket and eventually realized it was a paper ticket from AA which their systems don't support. My main complaint was the attitude from the BA team and their statement that BA was trying to get the maximum amount of revenue from any distressed passengers since Covid wasn't BA's fault. Anyway, back to AA after 45 minutes at the BA counter and it turned out there was a single keystroke missing on the AA ticket which made it default to a paper ticket. Took about 15 minutes to figure out the error but again, the attitude was great and then I was back over to BA to check in. Flights on BA were fine albeit an hour late which made for a rushed connection from T5 to T2 in LHR. Anyway, five stars (out of five) to AA for everything.
With another ticket, LH said they would process a refund for a flight they cancelled over a month ago which still hasn't hit my credit card.