Why It Costs Twice as Much to Fly Half as Far

In summary: routes served by multiple airlines will be cheaper.

A few days ago I wanted a one way flight from SYD to IAD, it was $1600. For fun I decided to see how much a round trip would cost: I bought it for $1100.<p>It's $500 cheaper to get a round-trip ticket than to fly one way from Sydney to Washington D.C.

I remember a similar situation from the news a few years ago. May have been in Indonesia, though I can't remember clearly anymore and Google isn't helping me.<p>Basically a flight between A and C which stopped at B (for refueling or to take on extra passengers or something) was cheaper than a flight from A to B. But for some reason the airline would only sell tickets from A to C with the condition that you could not get off at B. Some guy flew from A, tried to sneak off at B, and got caught. He claims the security guards roughed him up, and tried to sue the airline.

Airlines can prevent you from boarding if you travel part of a route you booked by alternate means? I'm not generally much of a fan of government intervention in private business, but that should probably be illegal.

When traveling a year ago I discovered that:<p>In south america, many of the one-way flights costs more than return.<p>And it was cheaper to fly from Rio to Bogota via (get this) Miami !

I've recently booked a flight from the UK to Utah, getting the return was cheaper than getting the single (by a couple of $100). Remind me why the airlines are losing money again?

Recent real life example : To go from montpellier (a south of france city ) to corsa (a south a france island ) it cost less to fly by London first...