Over the weekend, Qantas Airways set a new record with a nonstop ultra long haul flight from New York to Sydney. At a distance of 16,200 kilometers and a duration of 19 and a half hours, this is now the world's longest flight. Though, this was still a test voyage. It remains to be seen whether this will be a commercially viable route. The company also plans to offer a similar ultra long haul from London.

It's fascinating to think about the logistics that go into a flight like this. The flight took off with its fuel tanks maxed out at 101 tons. But according to Wired, the loss factor on each additional ton of fuel is about 60% simply because of the additional weight. In other words, most of the incremental fuel to get all the way to Sydney just gets cannibalized by the heavier load. Wow. That doesn't feel all that sustainable.

Similarly, every ten passengers roughly equates to one ton (200 pounds per person). So there's a balancing act between reducing weight (optimizing fuel consumption) and maximizing revenue (adding lots of people). There's also a question of how best to price discriminate across economy, premium economy, and first class.

Initially these ultra long haul flights were imagined to be flying hotels, where people could sleep, workout, and do all sorts of other things while they traveled halfway around the world. But the economics didn't work. Too much wasted space on non-revenue generating items.

The other interesting thing about these ultra long haul flights is how much work goes into passenger comfort, specifically around our body's natural rhythms. Angus Whitley of Bloomberg was onboard this maiden voyage and he talks about how the food they served -- spiced with things like chili and lime -- was designed to fire up your clock when you shouldn't be sleeping.

And this isn't new a feature of ultra long hauls. Qantas already employs things like hot chocolate laced with tryptophan in order to help people sleep onboard. I'm not great at sleeping on planes, generally because I don't fit in the seats very well. But maybe it's because I've been passing on the hot chocolate.

Image: Qantas via Bloomberg