What about de-icing costs?
I'm not sure what my airline would pay per liter of deice fluid, and I wonder if, like gas, a hedged cost. But, a quick search showed a 55-gallon drum of Type 1 runs US$1,930 and Type 4 runs USD$2,560. 55 Gallons is 208 liters. I have a picture from ground school that shows the minimum amount of de-icing fluid to be applied to a 737 is 185 liters to ensure valid holdover times are met for the wings and stabilizer - not to also remove contamination or to then apply Type 4. Given many airlines have aircraft much larger than a 737, I'd argue that most airlines are paying tens of millions.
But we could argue that it would be close to a drum per frost spray, and possibly as much as two drums of Type 1 and 1 drum of Type 4 to remove ice and add protection in active conditions for a 737. So, call it between USD$1,930 to $6,420 for a single 737. In the discussion about Canadian carriers, that's CAD$2,622 to $8,724 per tail. But then, just this last week we had a case where we also needed our radome and fuselage sprayed because of heavy snow build-up. The fuselage area of the -800 is a few hundred square feet less than the wings, but let's say it uses another half drum or so to de-ice the fuselage...that puts us at over CAD$10,000 per tail. That's going to be an overestimation, and it's not normal to get the whole plane done, so I'll stick with the previous figures as they keep us in the ballpark.
The busiest de-ice pad I saw this past week was in Calgary. We had 6 company airplanes being de-iced and another 6 waiting behind us. I don't know how many others were waiting on the taxiway or at the gates, but all needed to be de-iced and anti-iced, so let's say that's at least CAD$100,000 just from what I could see out the window. That storm didn't last all day though, and it's possible that the storm only affected 20 or 30 flights. But, I have seen days where every flight we have would need to be de-iced. Given the number of departures we have from that one airport on a day, that could be a de-ice bill of between CAD$524,400 to $1.74 million.
Now, that type of storm doesn't happen every day, nor do they often last any more than a morning or afternoon - and then they might only happen twice a winter, if that. I've had whole years where I de-iced maybe once or twice from September to April, and other years where I've de-iced four times in a day, but did that only two or three times. I'd say on average, I might de-ice once or twice a week. But across a fleet and all of winter, we can see it can rapidly increase into the tens of millions range, so not an insignificant consideration for a ULCC that operates in a country where if you want to fly, you can't avoid de-icing.