At long-haul distances, a refueling stop saves fuel, even taking into account the extra take-off and landing. Taking off with all the fuel to make it to your destination means taking off with a lot of weight. And a larger aircraft to fly with long-haul tanks that will eventually be empty is inefficient too.
This is called "Intermediate Stop Operations". Of course, there are other costs beyond fuel (landing costs, staffing costs, etc.), but sometimes you can make this an advantage (e.g. staff always sleeps at home base each night).
> In some studies it was found that fuel savings are in the order of 13–23 % (the longer the mission, the more fuel could be saved) for missions with a single stopover if aircraft are used that are optimized for shorter ranges
There are a very long list of reasons it’s normally sub optimal.
First your generally going out of the way to stop at an airport which means a longer trip, plus you need to climb back to altitude which means lower efficiency. Landings and takeoffs are harder on many systems which means more maticance. Time a major factor as not only are aircraft doing fewer routes passengers are also waiting around. Safety is another issue for adding stops, landing and takeoffs are much higher risk. Etc
It can be a net benefit, but normally your much better served to make every stop a significant destination rather than just being for fuel.
That's where it can become more viable: When you go A->B->C instead of A->C, you have two more origin:destination pairs that you sell tickets for, depending on (?uhhhh, 5th?) freedom rights.
I often use Iceland as my example, but same idea. I’m surprised WOW airlines failed though.
As much as people hate it (especially if someone else is paying the fare), I think long-haul’s days aren’t looking great. As fuel/biofuel becomes a bigger $ proportion of tickets, multiple medium-haul hops is going to become the way.
Take into account service fee charged by airport, because landing and refueling cost is not just fuel cost but also bunch of operations by ground personnel.
I think most expensive would still be gaining altitude - but I got down-voted so might be that my understanding of this is not that good.
The math is counterintuitive but planes fly with minimal fuel because fuel is so heavy that having more fuel requires even more fuel. Fuel is a primary expense. So airlines like to stop places even when not strictly required. They don’t fill the car all the way up like you and I might.
The math isn’t counter intuitive at all. Also how rockets work (burn a lot of fuel at the beginning because you have to push a lot of fuel + cargo), also let’s drop some boosters while we are at it to get rid of even more weight.
In flight refueling might be the way to go, but then keeping the fuel plane up also takes fuel.
