DOC
This is an interesting experiment, but it seems to miss the direct flight cost of operating the aircraft (beyond fuel), assuming the “increased fuel” is simply a proxy for increased flight time. That may, or may not, be significant depending on type and operation, but it should be modelled explicitly.
I’ve done some work on building a crude cost index for business-jet trips, and found that getting accurate inputs is difficult. In most cases, though, flight hours were more expensive than fuel burn, so omitting time-based operating costs risks understating the true impact.