@Caerfinon Thank you for the information. i've also found this: "siteValueModifier = [4,1,1.25,2,1,4,1,2,1,1,2,3,1,3,2,1,2,1,3,2,1,1]" piece of code on line 48 which may help, by for example giving airport further away more site value. The issue im facing with the rewards for airline missions was that "The Island Airport" (the closest airport to the ksc) mission which only required me to take 5 passengers. was giving more funds than flying to "cape kerman space center" with 16 passengers, and cape kerman space center is much, much further.
(edit: i have modified the site value of airports to be consistant with the first site value in the piece of code, 4 divided by 33, 33 being the distance in km from the ksc according to an other line of code near it, the product of the equation is an infinite loop of 0.1212121212. which i then multiplied to the distance of all airports, giving a balanced and accurate amount of funds that i should get from each airline mission)