The Concorde mainly transported fuel across the Atlantic so that enough was available to land safely. Passengers were just an extra on top. Also, being first-class only, it held fewer passengers than what low budget airlines have taken to cramming into their planes lately. To look at the structure relative to passengers is a bit misleading. Let's look at the fuel load and the mass fraction of empty weight relative to MTOW instead: | | 747-100 | Concorde | | -| -| -| | MTOW | 333.4 tons | 186.88 tons | | Empty mass | 162.5 tons | 78.9 tons | | Fuel | 183,380 liters | 119,800 liters | | Fuel to empty mass | 1.1285 L/kg | 1.5146 L/kg | | Mass fraction of empty to MTOW | 48.74% | 42.22% | If you compare passengers plus fuel to the empty mass of each airplane, the Concorde actually comes out well ahead of the 747 and looks like a prize of lightweight design. Having structurally efficient delta wings helped and should explain most of the difference.