If we really live on flat earth then we can start making money with long distance transport. I did some calculations. Earth radius is 20,000 km, so equator radius is 10,000 km. All this is going to apply only to north side of equator. I'm not very apt in mathematics any more so correct me if I am wrong.

Equations were taken from

http://mathforum.org/dr.math/faq/formulas/faq.circle.html:

theta - central angle

theta = arc/latitude radius (radians)

chord = 2*latitude radius * sin(theta/2)

and I calculated the chord for following latitudes and arcs

arc - 1000 km

latitude radius - 2500 km

chord - 993,4 km

you can make path shorter 6,6km for 1000km

arc - 2500 km

latitude radius - 2500 km

chord - 2397,1 km

you can make path shorter 102,9km for 1000km

arc - 5000 km

latitude radius - 2500 km

chord - 4207,4 km

you can make path shorter 792,6km for 5000km

arc - 2000 km

latitude radius - 5000 km

chord - 1986,7 km

you can make path shorter 13.3km for 2000km

arc - 5000 km

latitude radius - 5000 km

chord - 4794,3

you can make path shorter 205.7km for 5000km

arc - 5000 km

latitude radius - 10000 km (equator)

chord - 4948,1 km

you can make path shorter 51.9km for 5000km

arc - 8000 km

latitude radius - 10000 km (equator)

chord - 7788,4 km

you can make path shorter 2211.6km for 8000km

So, as you can see the path is sometimes significantly shorter than it is now when all transport goes with RE logic. If you can cut your expenses and shorten you 8000 km flight path near equator some 2000 km then you are a Winner! Even near the north pole you can cut some 100 km for 1000 km flight. It's not much but it's something. Just think about it, you can really make money if you travel along your FE shorter path on northern side of equator, just grab the opportunity!