It's right on the wikipedia page, under "Operations":
> In 2018, the US airlines had a fuel consumption of 58 mpg‑US (4.06 L/100 km) per revenue passenger for domestic flights
We should take a system-wide view. The relative efficiency of any particular plane is irrelevant if the entire system depends on other, wasteful aspects. Let's consider the energy required to run an airport, including the infrastructure leading to the airport.