While much more fuel-efficient aircraft are increasingly replacing the Boeing 767, it is still going strong, particularly for freighters; much lower ownership costs help. Examining OAG data shows 15,100 scheduled passenger roundtrip flights on the twin-aisle type in August. Flights are on the 767-200ER (really!), 767-300 (non-Extended Range; just one is operational), 767-300ER, and 767-400ER variants.