Round trip versus one way airfares
 

We need to book a one-way flight between Santiago and Buenos Aires. One of my guide books said to check out round trip fares, because they are often cheaper. And, this seems to be true. On LAN on our date, the one-way fare is $485, the round trip is $240. I know that in the U.S., the airlines won't let you get away with booking a round trip if you don't use both segments. Is it different in South America?

The same holds in SA. How do U.S. airlines penalize you if you do not fly the return leg? Also most U.S. airlines now let you fly one way for exactly half the price. I checked out similar fares in SA and found it was cheaper to buy rtp.

In theory, the airline could charge you the difference in fares. You probably paid for the ticket with a credit card, so they'd those numbers. Do they actually go to the trouble of doing that? I don't know, but you wouldn't have a leg to stand on to protest it if they did.

I'm not aware of an airline ever "following up" to charge you for an "additional" half segment of the flight that you "missed." Indeed, good luck to them if they tried to do so. You decided not to take the return flight. On that basis they can recover the "other half"? Very unlikely. You have already paid the "full price" of the ticket you booked. Moreover, an airline can't simply "bill you" for some additional charge like 50% more for the ticket price. Such a provision would have to be in the contract of carriage, or the rules of the ticket you purchase. I've not seen such language in any tkts I have purchased, "that in the event you don't fly the full roundtrip we reserve the right to charge you some unknown amount of money for the return leg you didn't fly on."

loots of people do not use the return

routinely US/SA/worldwide

Cheap R/T almost always better

Your choice to fly it or not without penalty

They can't come back and charge you. Everyone would just file to deny it on their credit card if so. Book the round-trip, throw away half.

I've never heard of a case either where an airline has later charged the difference for the fares. It would be a lot of trouble to go to. I'm saying they could make a case that it's justified if they did and someone tried to deny that charge on their credit card.

Thanks for all the replies. I don't know of anyone this has happened to in the U.S., but I thought I read a couple years ago that U.S. airlines would bill you for the difference between one-way and RT if you didn't take the entire trip. Otherwise, why wouldn't everyone just book a round trip? And I really don't understand what possible justification the airlines have for charging more for a one-way than for a round trip! I don't think they do this quite as often anymore, but LAN certainly does! Anyway, I've found a decent one-way fare on Air Canada.