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Hypothetically the survival of the planet depends on getting someone from London to Sydney in the quickest time possible.
This person isn't a pilot so he will need to be passengered there.
How are we doing it?
Direct flight using that long-range Airbus that flew last week. Assuming the survival of mankind depends on it, I'd imagine that certain rules could be waived. It'd be about 22 hours I think.
Back of a two person fast jet, tankers on call the whole way and throttles all the way to the wall.
The brief does not define the challenge in much detail.
There is a Sydney in Nova Scotia.
It is about a quarter of the distance away from London as the Sydney in Australia.
And I know someone named Sydney who lives in London. Getting to them would be much quicker.
Sydney the one in Australia and the English London.
Surely a jet fighter would have to go slow when refuelling so would a commercial plane overtake it?
Possibly, but you could negate some of that by having the jet fighter take off from a treadmill.
It would take a while to get the tankers in the right place for a supersonic military jet so probably not the quickest option. It appears any empty A380 can do it in one stop (they've flown back to Germany empty for servicing) and hopefully there'll be one ready to fly at Heathrow or Gatwick when you want to go. So helicopter to the airport 15 minutes, fly to Sydney airport 19 to 20 hours, helicopter to where you need to be 15 minutes.
The quesation was fastest way, so I would pre-position tankers, then start the clock. As for slowing down... The fighter would be going as fast as a KC-135 (or similar to a380) when it was tanking and then much, much faster when it was not, so I think it would be the fastest way (until sub-orbital passenger rockets).
Hang on, I am asking AI...
Qwen says:
Under the exact hypothetical conditions you've specified, the flight would take approximately 5.5 to 6.5 hours. Here's a clear breakdown of how that figure is derived and the important contextual factors:
🔹 Core Calculation
Distance: The great-circle (shortest) distance between London and Sydney is ~17,000 km (~10,560 miles).
F-15 Maximum Speed: Officially rated at Mach 2.5. Because the speed of sound decreases with altitude and temperature, Mach 2.5 translates to roughly 2,600–3,000 km/h (1,600–1,860 mph) depending on flight level. Using a representative cruise/maximum airspeed of ~2,800 km/h:
Time = 17,000 km ÷ 2,800 km/h ≈ 6.07 hours(~6 hours)Wind Effect: Upper-atmosphere wind patterns (jet streams) typically add or subtract 150–300 km/h to ground speed along this route. This shifts the theoretical time to roughly 5 to 7 hours.
🔹 Important Caveats & Realities
While your scenario removes fuel range as a limiting factor, several physical and operational constraints would still apply:
Aircraft Design Limits: The F-15 is optimized for short-range air combat, not sustained high-speed transit. Flying at Mach 2.5 continuously would require constant afterburner use, generate extreme thermal stress on the airframe and engines, and quickly exceed maintenance/structural limits, even with unlimited refueling. Realistic high-speed transit would likely be capped at Mach 1.5–1.8 for extended periods.
Wind & Routing: A true great-circle route over London to Sydney crosses Europe, the Middle East, India/Southeast Asia, and the Pacific. Weather patterns, especially the subtropical jet stream, would significantly alter ground speed depending on routing. Tankers can only fly at their own speed limits (~Mach 0.9–1.2), so they'd need to reposition or use specialized support aircraft to match an F-15's high-speed track.
Airspace & Sovereignty: This path crosses numerous restricted, denied, or politically sensitive airspace zones. In reality, obtaining overflight clearance would be impossible without extraordinary diplomatic arrangements, and military aircraft routinely avoid such routes for operational security.
✅ Bottom Line
Under your strict theoretical assumptions (maximum airspeed, unlimited pre-positioned tankers, direct route):
⏱️ ~5.5 to 6.5 hours elapsed time.In any practical military or civilian context, the flight would be impossible due to airspace restrictions, aircraft thermal/engine limits, and tanker speed mismatch, not fuel range. Let me know if you'd like a breakdown of how real-world supersonic transit is typically planned or how tanker coordination actually works at high speeds.
Taking an empty A380 would probably be the better choice, you'd have access to snacks, films, the bar. You could go for a walk...
The range of a fighter jet at full whack though is not great. It'd need a shedload of pre-positioned tankers; you'd be better off in some sort of just subsonic thing with much longer range and fewer refuelling stops.
B1-B would be my choice.
Ooooooh! I wonder if you could break an SR-71 out of retirement and use that!
Ok, so apparently the Bi-B would take a bit longer... Qwen thinks it would be between 12 and 15 hours depending on the winds at height based on the airframe design and engines, whereas the SR-71 would take between 4 and 5.5, primarily due to the optimisation in the airframe, engines and fuel for high altitude, continuous high speed.
But, again, no snacks.
Taking an empty A380 would probably be the better choice
I'd prefer one with a pilot myself.
Do they really need to be there, or could we do what is needed on Teams?
Do they really need to be there, or could we do what is needed on Teams?
Mission Impossible would have been a really short (and very dull) franchise if Tom Cruise could just have had a Teams call, run a few ideas up the flagpole, leveraged the assets and got all his ducks in a row.
All things considered, I'd say that the F-15 idea is too fraught with risk. Sure, it'd be quick IF it gets there, but the consequences of it not getting there are fairly serious, especially with the need for all the KC35 en route etc. I'm going to stick with my Airbus 350-1000ULR plan. It flew 12,460nm in a flight time of 24 hours and 24 minutes, so approx 20 hours for the 10,560 miles needed. You set off in your F-15, I'll jump in the Airbus. I'll see you when (if) you get there.
I'll be in the Opera House bar sipping a G&T...
Falcon9 surely?
Make your way to Paddington - from theres its 12 minutes by bike
https://maps.app.goo.gl/fZ3zYuqqnw5yBZRX7
Kings Cross looks closer as the crow flies but actually takes a minute longer by bike
https://maps.app.goo.gl/vddjNWrMHEBZytoX8
High altitude balloon ?
You go up, skirt across the top a bit and back down. Distance is shorter the higher up you are.
