More realistic fuel burn differences
Using maximum fuel range instead of typical range for (probably?) more accurate calculation of aircraft fuel burn
Obviously, I know nothing about game creation or balance techniques, but the way fuel burn is calculated in the game right now, there is a very vast difference of the fuel cost per pax/mile between different aircraft types. This makes a handful of aircraft (a321neo, a223) extremely profitable and thus much more preferred by players, while most of the others are not used at all, despite being very popular with real life airlines. Also, within some aircraft families it gets weirder, for example a220-300 burning less fuel than the smaller a220-100.
I was thinking this is due to the varying definition of "typical range" different manufacturers give to their aircraft. Maximum fuel range on the other hand is directly correlating to aircraft frame weight and fuel capacity, while also taking in account the aircraft family's engine and flight characteristics. It's the maximum still air range a plane can fly with full fuel tank and no payload onboard, including taxiing, all flight phases + reserves. Payload/range charts can be found readily available for all Airbus, Boeing, Embraer and Bombardier aircraft. For example the documents for Boeing are on https://www.boeing.com/commercial/airports/plan_manuals.page
I made a spreadsheet using that range from all the charts I could find as base for fuel burn. https://docs.google.com/spreadsheets/d/1Ya_AgyrdNk_nDVl6D1M4O2-f52J0lhOy9yvaDpayD4Y/edit?usp=sharing Looking at for example 737 or 320 families you can see how they are now comparable, as in real life. Also, a321neo now has higher fuel burn than the smaller a320neo, but lower that the previous generation a321. Low capacity/range aircraft and turboprops are still broken though. Adding the 200nm from the reserve fuel to the range seemed to help a bit.
Overall most of the aircraft get lower fuel burn (comparable to what the a321neo and a321neoLR have now - the new calculation doesn't change them), 21% decrease on average. CS300 seems to have been increased a lot, but I found this from Wikipedia (the source is behind a paywall https://aviationweek.com/crossover-single-aisle-jets/airlines-praise-c-series-performance-manage-early-issues):
The CS300 burns 20% less fuel than the Airbus A319, 21% less than the 737 Classic
Checking, the calculated burn is indeed 18% less than a319 and 22% less than 737-300