Like it or not, we're entering the era of ultra-long distance travel – a world where flight times can stretch to 20 hours and stopovers are optional.

It could be argued that we're already there, at least in the case of Qantas' daily Airbus A380 flight between Sydney and Dallas/Forth Worth. This one already pushes the envelope for the superjumbo's range, at around 15 hours for the QF7 flight from Sydney to Dallas and 17 hours for the QF8 return leg.

But the non-stop heroes of 2018 will be flights to London and New York by Qantas and Singapore Airlines, respectively.

Qantas last month launched its direct Perth-London flight on the Boeing 787, yet for all the fanfare surrounding the red-tailed Dreamliner forging the first direct link between Australia and the UK, only some of its passengers will be Perth residents.

Qantas wants to see travellers from the likes of Sydney and Melbourne jet across to Perth on a domestic flight and then step onto the Boeing 787 to begin their non-stop journey to London rather than take the more traditional Kangaroo Route via Singapore.

By the end of this year, Singapore Airlines will also redraw its network map with non-stop flights to New York and Los Angeles.

Those flights, which will rely on a special ultra-long range version of the Airbus A350-900, will offer a welcome alternative to SQ's current New York-via-Frankfurt and LAX-via-Tokyo or Seoul.

But how much time do these non-stop flights really save the average traveller?

Qantas non-stop to London

Let's start with Qantas' Perth-London flight. It's a clear-cut alternative to the airline's flagship QF1 from Sydney to London, which now goes via Singapore rather than Dubai, and Sydney is of course Australia's largest city and thus where the largest pool of potential travellers could be drawn from.

Qantas lists the total travel time for Sydney-Singapore-London (including the short stopover at Singapore) as an even 24 hours.

Flying Sydney-Perth-London – the first leg on a domestic Qantas flight, the second to connect with the non-stop Dreamliner on QF9 – takes just over 25 hours, and if you scooted from Sydney to Melbourne to connect to QF9 at the very start of its journey you're up for 26 hours.

So at best, a traveller from Sydney will spend one more hour if they choose the 'non-stop' option of Perth-London (which is a non-stop only if you're starting out from Perth).

The upside, at least for some, is that most of your flying time will be spent in a contiguous block of 17 hours from Perth to London instead of 7½ hours from Sydney to Singapore and then 13½ hours from Singapore to London.

What about Melbourne? As it happens, the Victorian capital can claim the best of both worlds. Travellers can hop onto QF9 for a Dreamliner-all-the-way flight to Perth and onwards to London – a 23 hour journey – or fly north to Singapore and connect onto QF1 to London, a trip of just under 24 hours. 

Singapore Airlines non-stop to New York

As we've previously reported, the tail end of this year will see Singapore Airlines restart non-stop flights from Singapore to New York.

How will that change the lot of the business traveller?

SQ's current flights to New York take a globe-striding route via Frankfurt. We flew this route just last week, ahead of the delivery flight of the Boeing 787-10 from Boeing's South Carolina facility back to Singapore – and at just over 23 hours, it was quite the marathon.

By comparison, the non-stop Singapore-New York flight will cut a direct path over Asia and Alaska and is expected to do the trip in 18-19 hours. That's about half a day saved for the busy executive, and once again there's that contiguous block of time in which passengers can maximise their sleep, work and relaxation.

Qantas 'Project Sunrise' non-stop to London, New York

Push the clock forward five years and Qantas hopes to be running direct flights from Sydney and Melbourne to London and New York, using either the Airbus A350-900ULR or the Boeing 777-8.

As is the case with Singapore Airlines' looming New York direct flights, this is going to slice quite a few hours off the clock.

Qantas estimates a 20 hour trip to London – four hours shorter than the Airbus A380 via Singapore – and around 18 hours to New York, saving three hours over today's QF11 and its LAX stopover.

(Given those long flights, little wonder that Qantas is considering a 'sleeping berth' cabin class and dedicated exercise areas located in the cargo area beneath the main deck.)

Qantas CEO Alan Joyce sees the benefits as doing beyond "a faster trip door to door."

"Removing the need to stop mid-way means your journey is uninterrupted. Less chance for delays on the ground; more time watching movies and sleeping."

Also read: Qantas wants four classes, 300 passengers in ultra-long range jets