The only global number was: “In 2018, CO₂ emissions totalled 747 million tonnes for passenger transport, for 8.5 trillion revenue passenger kilometres (RPK), giving an average of 88 gram CO₂ per RPK.[2] A 88 gCO₂/km represents 28 g of fuel per km, or a 3.5 L/100 km (67 mpg‑US) fuel consumption.”
Anyway that’s not measuring direct fuel consumption in flight but estimating fuel used by the industry to transport passengers. Sort of like including fuel transportation costs to gas stations as part of a cars fuel efficiency. It’s also using US numbers to do so which likely overstate fuel consumption.
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.
First that’s excluding more efficient long haul flights. If you want a system wide view then you also need to include the costs associated with building and maintaining rail/road networks etc.
Also just like road, rail, and boats aircraft don’t get to fly hypothetically ideal paths from origin to destination. Actual MPG is distance traveled / fuel used not distance from the origin to destination / fuel used.
Not to mention most commercial flights are also moving freight on those same aircraft but that’s secondary.
The only global number was: “In 2018, CO₂ emissions totalled 747 million tonnes for passenger transport, for 8.5 trillion revenue passenger kilometres (RPK), giving an average of 88 gram CO₂ per RPK.[2] A 88 gCO₂/km represents 28 g of fuel per km, or a 3.5 L/100 km (67 mpg‑US) fuel consumption.”
Anyway that’s not measuring direct fuel consumption in flight but estimating fuel used by the industry to transport passengers. Sort of like including fuel transportation costs to gas stations as part of a cars fuel efficiency. It’s also using US numbers to do so which likely overstate fuel consumption.