Speaking about the British Airways Boeing 777 fleet exclusively, there are four different seat maps for the aircraft: 777-200ER with first class, 777-200ER based at LGW, 777-200ER, and 777-300.

British Airways ... than United. Japan Airlines (JAL) uses its Boeing 777-300ERs (77W), which although larger than the Boeing 787-10, are configured with fewer seats. JAL’s 77Ws have 244 seats ...