Had a short look at your airline:
Minneapolis: You use one of your 757 to fly to and a MD-80. But your competitor uses 2x B737 and they are smaller than both of your aircraft, so he has more market share, needs less fuel and has similar pax numbers.
Newark: You only fly there only six days a week and only with one MD-80, but demand on this route is >2000 per day.
Boston: You fly there every day, but only two times with MD-80, but demand is >1000.
Atlanta: Four times a week, one MD-80. Demand >1600
Denver: Nice one! Maybe there is space for the B757 that flys to Minneapolis at the moment? You could catch the last business class seats and fill up demand to 100%.
Phoenix: Good one, but maybe you should add another aircraft. I would suggest something smaller than a MD-80, but you don't have... it's only to fill up demand and increase flights per day.
Dallas: Nice, but why the hell Finnair has this much market share with his B747-400? Is your Company Image very low?
-> Some hints:
Fly big routes as often as you can, minimum demand 100%, better 120%. Also catch Business Class seats if possible, but don't reconfigurate old used planes.... only those who you get new (= no configuration costs) or aircraft from the used market which are nearly new and you know you use them 6+ years.
Raise your CI. Never spend money for Route Image, but the target for Company Image should always be >90.
The problem are not high fuel costs, it's your high personal costs due to serving too much airports with wrong aircraft respectively not often enough per day or not every day.