Air-travel fuel consumption is typically given as a per-trip total. That's averaged over a range of trip lengths.

Though yes, take-offs add considerably to the consumption. Landings don't, as aircraft are typically gliding in at or close to idle thrust.

Efficiency for very-long-range flights is actually reduced as total take-off weight (TOW) must be reduced, exchanging payload (passengers) for fuel.

For very short flights, fuel burn is about 10l/100km-passenger. At intermediate ranges, that falls to about 3l/100km-passenger. See:

https://www.fzt.haw-hamburg.de/pers/Scholz/arbeiten/TextBurz...