There are few aircraft as iconic as the Boeing 747, a lumbering four-engine quadjet with an iconic hump and unmatched passenger capacity. The jet, once the go-to aircraft for all kinds of long-haul travel, is seldom used by passenger airlines today. Only a handful of airlines still have the model in service, and only Lufthansa, Air China, and Korean Air operate the aircraft’s most advanced passenger variant, the 747-8i.