…that’d be me then!
A typical flight from Edinburgh to London would use around 3000 litres of Jet A1 (diesel).
As a rule of thumb, for every extra ton of fuel we carry on a longhaul flight, we reckon on burning around 20% of that fuel, just to carry it - but that’s on a 10 hour flight. Over a single hour we could roughly equate that to each ton costing us around 2%.
The flight from Edi to LHR is almost exactly one hour, each passenger, with bags weighs roughly 100Kgs, and so each passenger would ‘cost’ roughly 2Kgs of fuel to carry over and above what it’d cost in fuel terms to operate the flight without them.
So 2.5 litres of fuel (specific gravity of Jet A-1 of roughly 0.8) can be attributed to each passenger flown. Pretty efficient if the flight is going anyway!
The total per passenger, on a full flight, is around 17 litres. So the aircraft would be burning 14.5 litres per seat, whether there was anyone in it or not!
Of course, aircraft don’t just carry passengers, we carry quite a lot of time critical freight, and post too - I’ve even carried live organs for transplant.
Even at 17 litres per passenger (worst case), it’s still far more efficient than a car (electric cars aside).
As I say though, if you know the flight is going anyway, travelling on it is only going to ‘cost’ an extra 2.5 litres of fuel - which makes it the cleanest option (with a touch of perverse logic applied, admittedly)!