(CNN) — There's a lot of ballyhoo made about new, lighter planes opening up ultra-long routes.
What we often forget is that for at least 10 years now, there have been planes perfectly capable of flying massive distances, known as Ultra Long-Haul Routes (ULR).
Until 2013, Singapore Airlines used the Airbus A340-500 to fly between Singapore and New York, a distance of 15,400 kilometers, which was then the longest flight in the world. Qatar Airways flies the Boeing 777-200LR from Auckland to Doha, a distance of more than 14,500 kilometers, and Emirates flies the Airbus A380 on its Dubai to Los Angeles run.
Costs vs revenue
The real challenge has always been to make these routes profitable. (Or, at the very least, not lose too much money.)
Like any business, the economics come down to balancing costs against revenue. For an airline, this means comparing how expensive it is to operate a particular aircraft (fuel costs) to the number of "passenger holds" (demand for specific routes).
Let's take the old SQ21, from Singapore to New York. The A340-500 could certainly handle the range. But the plane is a four-engine, heavy aircraft that guzzled fuel.
When the oil price shot up, this expensive flight suddenly became barely profitable. Don't forget, the longer the flight the more fuel you need to carry. You end up carrying fuel just to carry the fuel! Fuel takes a greater a proportion of the total cost as a flight's length increases.
A lightweight, twin-aisle Boeing 787 Dreamliner arrives at Sydney International Airport.
TORSTEN BLACKWOOD/AFP/Getty Images
Then there's the question, can you fill all the plane's seats on that route?
For example, the superjumbo A380. The plane has four engines, uses older technology, and can fly up to 500 people in first, business and economy classes ... Or the 777-200LR. Even with only two engines, it has a heavy, aluminum fuselage and carries more than 300 passengers.
Filling either of these planes every day on "long, thin routes" -- long-distance, low demand -- such as Perth to London is very difficult.
That is why there has been such increased demand for newer, lighter planes like the Boeing 787 Dreamliner and the Airbus A350-900ULR. Their engines sip up to 20% less fuel and carry fewer than 300 passengers.
It means airlines can open up routes like Perth to London, or Air New Zealand's planned Chicago to Auckland flight, where there will be lower demand.
Of course the A380 and the 777-200LR will be with us for many years to come. What will change is the number of new routes offered by these newer planes, which will create a whole new sector of commercial flight.