Longest possible route

I'm trying to find out the longest distance between any two airports in any region. Demand doesn't really matter, two airports that are unavailable for lease or has little to no demand still makes this list. The longest route I know is MPL-CHT, with 12,404 miles distance. If anyone knows any route that is beyond this distance I'd really appreciate if you just let me know.

Interesting challenge... I get routes over 12,000 all the time in China so I'd recommend to search in Asia. The first or second I tried to find over 12,400 was PVG and I got a longer one, PVG-STY 12,405 mi.

Look at this...

https://en.wikipedia.../wiki/Antipodes

... so you're most likely find most of them between East-Southeast Asia and South America, or much less between Iberian peninsula and New Zealand, maybe some between Pacific and West Africa.

Although I'm not sure what you mean by "longest possible route" in AE because neither A340-500, A350-900R, 787s nor 777-200LR can go over 12,080 mi even with 1 passenger (in real commercial aviation it would be even less acceptable even to go over 10,000).

Had a look around, here's a couple of the longest routes:

Hong Kong to Tarija is 12326 miles,

Padang to Tumaco is 12331 miles,

Perth to Bermuda is 12383 miles,

Christchurch to La Coruna is 12384 miles,

Madrid to Palmerston North is 12385 miles,

Palembang to Neiva is 12385 miles,

Esmeraldas to Aek Godang is 12390 miles,

Nelson to Braganca is 12391 miles,

Tianjin to Bahia Blanca is 12391 miles,

Honolulu to Ghanzi is 12392 miles,

Tauranga to Jaen is 12396 miles,

Kuala Lumpur to Macas is 12396 miles,

Gibraltar to Whangarei is 12398 miles,

Wellington to Salamanca is 12400 miles,

Shanghai to Salto is 12405 miles (as Konj said),

Tangier to Whangarei is 12415 miles,

Puerto Natales to Ulan Ude is 12420 miles,

and the longest I've found so far is:

Wuhai to Valdivia is 12429 miles

I tried but the longest i can come up with is... PIO to REP at 12407 miles

Are any of these routes profitable?

I highly doubt it. Those routes are too long even for the 772LR, and you'd have to practically be a business jet (in the 772LR) to even think about reaching them. By then, your profit is slim at best. There's also little to no demand in any of these routes (betting the most Y demand is 100), so it's not. At all.

I'd say the longest possible route would be JFK-JFK, or LHR-LHR, or HKG-HKG, etc, etc

Kek.

Actually since the Earth bulges along the equator, the longest possible route would be some airport on the equator to that same airport headed east or west along the equator. 

Are any of these routes profitable?

The question is not profitable, 10,000 mi routes are barely profitable, but they are literally not possible, because 772LR maximum range (for 1 passenger) is 400 miles short for them.

According to Wiki the 777-200LR can fly 17,600km with max fuel and 301 pax/crew. So the longest routes it could fly with reserves could be SYD-LHR and MEL-JFK. AKA routes that Etihad could cover with its 777s.

I've just found out SFD-MLG with 12,420 miles distance, but I think WUA-ZAL(12,429 miles, discovered by NNR) still holds the record. The theoretically longest possible distance between any two international airports is 12,450 miles, so I wonder if there's any more routes that could come near the upper bound.

According to Wiki the 777-200LR can fly 17,600km with max fuel and 301 pax/crew. So the longest routes it could fly with reserves could be SYD-LHR and MEL-JFK. AKA routes that Etihad could cover with its 777s.

?? Etihad? What does this have to do with them? It's not an Australian airline (or British or American), and they don't even have 772LR. They do have A345 that's about as long-range as 772LR (and actually A345 flew the longest commercial route), but how could Etihad fly those routes unless you brutally de-regulate the world market right now?

SIA quit its longest direct route SIN-EWR and is only thinking about returning with fuel price drops and when they get A350-900R, and that's the only thing that ever came close to 10,000 and even went over 9,000.

We'll have to wait for a while even for regular 10,000 mile routes like those above, even if there are planes that can actually do it, their efficiency is just not good enough. 12,000 makes no sense at the moment.

?? Etihad? What does this have to do with them? It's not an Australian airline (or British or American), and they don't even have 772LR. They do have A345 that's about as long-range as 772LR (and actually A345 flew the longest commercial route), but how could Etihad fly those routes unless you brutally de-regulate the world market right now?
 
SIA quit its longest direct route SIN-EWR and is only thinking about returning with fuel price drops and when they get A350-900R, and that's the only thing that ever came close to 10,000 and even went over 9,000.
We'll have to wait for a while even for regular 10,000 mile routes like those above, even if there are planes that can actually do it, their efficiency is just not good enough. 12,000 makes no sense at the moment.