[Pristina]

But you travel to get somewhere not to be in a vehicle for X amount of time. So why would any metrics besides per-distance be more relevant.

[heliodor]

As a traveler, I care about the trip, not the time nor the distance. If I take this trip, what's my probability of dying if I fly it versus drive it.

Airplane travel have fixed segments (takeoff and landing, ascent, descent) and variable segments (the coasting phase that varies by distance traveled). Car travel is only the variable segment. Hard to compare apples to oranges.