when comparing driving to flying between destinations, it's highly likely that the flight will have a shorter duration.
The big wrinkle in this comparison is that planes burn most of their energy in the ascent to cruising speed/altitude. Energy consumption per mile is likely to be much higher on a short hop flight where cruising altitude is never reached than a 12 hour transoceanic flight.
On the other hand short-haul flights don't climb to as high of altitudes. They only climb about 2/3rds as high. But then again the air is thicker so cruising is less efficient. Oh gosh, for want of data.
You have to assume that airlines have chosen a decent compromise here. Every wasted joule of energy translates to a higher fuel cost and a lower profit margin.
The big wrinkle in this comparison is that planes burn most of their energy in the ascent to cruising speed/altitude. Energy consumption per mile is likely to be much higher on a short hop flight where cruising altitude is never reached than a 12 hour transoceanic flight.