Those are marginal costs. Parent comment was talking about amortised costs, i.e. fixed costs. Such as the airplane, itself (depreciation per mile of flight asid

Those are marginal costs. Parent comment was talking about amortised costs, i.e. fixed costs. Such as the airplane, itself (depreciation per mile of flight aside, but that’s another point). https://en.m.wikipedia.org/wiki/Marginal_cost_of_capital https://en.m.wikipedia.org/wiki/Marginal_cost_of_capital