Originally Posted by
corporate-wage-slave
My suspicion is that this will be far easier to do on Air France, particularly if the dog is under 8 kgs (they probably won't weigh the dog so no need to put Rover on to a diet if just over!). Small dogs can travel in the cabin, though not in Business class. On BA the dog will have to go in the hold and be transferred at LHR, where they will be checked and looked after by the City of London Corporation Heathrow Animal Reception Centre during the transfer.
Yes, don't fly via the UK unless you absolutely need to. There are very strict rules about bringing animals into the UK even if you're just changing planes. In contrast, on most Continental European airlines he/she can travel in the cabin. Lufthansa might be a good bet.