A quick look at aeroLOPA's extensive database of airliner seat maps shows that United configures its Boeing 767-400ER aircraft in a three-class configuration that can accommodate 231 passengers.
United Airlines will operate its Boeing 767 ... layouts of Boeing 767-300ER aircraft and one variant of a Boeing 767-400ER aircraft: The first 767-300ER layout holds 30 passengers in Polaris ...