One thing that bothered me was that there is very little difference between the runcost of huge planes and small ones. It didn't matter if you had a 747 on each route or not, even if they almost always were close to empty. I came up with a equation that uses cargo capacity & aircraft speed to vary the operating cost.
This change means that its very important to choose the right aircraft. You can't run a 747 short haul with 1/3 loads and expect a huge profit, if at all (depending on delay at a busy airport). Same with concorde and other bigger planes. Basically, if you don't have the supply, don't use big planes. I had 737's make more money than 747's because i could fill the 737 on every leg but not the 747. The concorde is only useful on very long flights (do to its speed), near full cargo, and if almost no delay is encountered - i'd recommend the enhanced airport mod for the dual runways.
I also made other minor adjustments to a few planes regarding seating capacity (concorde now 90 and C130 now 60), and obsolete year so a diversified fleet is always availabe.
Overall, not much has changed in regard to Cash flow - that is, if the right aircraft is doing the right job. I still have 747's giving me 250k a month that are flying near full loaded routes. Other 747's that were previously not always full have been replaced with smaller planes, like a 737 - which is now giving me a cashflow of 50k a month instead of a negative value the 747 gave me. All this mod does is eliminate the one size fits all airplane.
As for the "secret equation" i used to come up with for the operating cost, the less seats and the slower it is, the cheaper it is. Speed is a big modifier for operating cost. If you fly short routes where the aircrafts speed can't fully develop, a slower plane is more favorable. Thats why i extended the obsolete year for the F27 - so ya got a nice regional airplane for short routes.
Below you'll find the stats. If any of you are interested, please review the information and post suggestions that i will then consider. After thats done, i'll release the mod if anyone really wants it

Code: Select all
* indicates Change from original based on 1970 $ inflation
ID Obsolete year Seats Speed Operating Cost
707 1987 160 604 67,124 *
737 none* 100 575 39,700 *
747 none 210 595 86,918 *
777 none 180 595 74,501 *
A320 none 140 595 57,945 *
A380 none 250 595 103,473 *
A5 Trimotor 1966 13 123 1,089 *
AB139 none 15 150 4,223 *
BAE 146 none 88 482 29,485 *
C130 none 60* 345 35,899 *
Comet 1985 90 532 33,196 *
Concorde 2003 90* 1355 84,637 *
DC-3 1975 24 150 2,500 *
DH-16 1945 4 100 270 *
F27 none* 55* 266 10,066 *
F7 1954 8 106 586 *
JU52 1965 17 152 1,771 *
S55 2000 10 90 2,816 *
Viscount 1985 40 302 8,447 *