If a jet costs $2,000 an hour to operate, and that cost is increased by $100 for a one hour flight, it's a 5% increase in operating costs.
As an example, if your aircraft burned 3,000 pounds per hour, or around 450 gallons per hour. Now double check my math on this one, because I'm pretty horrible at math, but if the price of JetA went up 20 cents from 4 dollars a gallon to $4.20 a gallon, you'd have the same result.
Now that's assuming that all stage lengths are 1 hour. As lengths go up, the price on a percentage goes down.
Again, folks are emotionally involved in this, not financially involved, and the results are somewhere between hilarious and ludicrous. These jets will not go away.