Originally Posted by StuMcIlwain

No, Airbus has to do an evacuation test before the aircraft can be certified using the maximum number of passengers that the aircraft has been designed for. The A321s were designed for up to 220 passengers, so neither Air Canada nor Rouge is at the limit yet. I think Airbus increased that number for the neos.

The 777-300 can carry up to 550 passengers.