Considering the most recent update has changed the aircrafts fuel income again (not by much), I’m suggesting fuel tanks. By purchasing fuel tanks at an airport, we can pretty much eliminate the fuel costs and earn the full amount on a route, as we already own the fuel. It allows more income and would generate larger profits, particularly at smaller airports where fuels costs can snatch half a flights revenue away, such as INN-TBS with the Saab 340.
I disagree with you, because yes, if you buy a fuel tank you can pretty much eliminate the fuel costs but, how can you recharge this tank?
I think that is better an ecnocnomic descount of fuel in her airplanes than add a new game mechanic.
Of course that is my humble opinion.
Just buy more fuel, simple. Saves money in the long run getting it in one bulk order.