booking air travel

Depending on the airline and the destination, tow one-way tickets can cost the same as a r/t and give you the flexibility to make a change if needed, at the least cost.

Internationally, what I have found to be most common is that a one-way costs as much (or more) than a r/t ticket.

I have found using miles ( Alaska) is r/t or open jaw is twice the cost of one way, so one can book it either way and the total miles needed is the same. How other airlines administer their 'miles' program may be different.

I have also found international one-way tickets to be more expensive than round-trip. Particularly the return ticket from Europe to North America. Once, in desperation, I used a ticket consolidator to get a return ticket from Germany. The consolidator confirmed that one-way tickets from Europe to North America were significantly higher than round trip.

For domestic travel within the US there doesn’t seem to be a price difference between round trip and one way.

Some airlines' business model is built around round-trip purchases; on those airlines, booking one-ways will be more expensive (in many case, much more so). I book one-ways using domestic carriers where I sometimes mix and match one-ways with 2 different carriers (e.g. Southwest and Alaska Air). I have done this with points too, in cases where I have only the required number of points for one carrier/ one way. Southwest has the most flexible model for both one-ways, free luggage, and easy cancellation policies.

I don't think I've ever booked international flights using one-ways - either within 1 carrier or 2 "mix and match" carriers - because, at least in the past, it was significantly more expensive. I do understand the flexibility sentiment of one-ways and why it would be attractive and preferred over having to rebook an entire round trip; I've just never been able to make it for for international flights. Plus, I don't want any issues (additional questions or attention) in Passport Control overseas where an agent would ask me why I have a one-way ticket only. That may be an insignificant concern, I don't know.

Yes, for sure, you have to do the homework. Lately, I have found that I can do domestic multicity at a huge savings. This fall, and the same for tickets I purchased for spring, I was able to add a leg creating a multicity trip on what would have been a round trip. For $15 more, I was able to have a stay in Seattle prior to continuing on to Hawaii.

Can you share what international airlines you've found this approach to be successful? I have no doubt that it works for some domestic carriers (maybe all 6? by now) but I'm not sure about international carriers. Granted, I haven't used budget carriers in Europe in the past so I have no knowledge whether those are good airlines for this approach.

A disadvantage of booking one-way tickets that has become clear to me these past 2 years is with respect to cancellations and refunds. When I was hoping for a cancellation (so that I could get a full refund of my ticket price) then I only needed any one leg of a round trip (or open jaw) ticket to be cancelled to become eligible for a full refund. If I had booked separate tickets, then one leg of each journey would have had to have been cancelled to get refunds for both.

Booking with miles -- on United the round trip is the same as 2 one-way. RT gives the option of adding a free mid-trip flight if booked at the same time. All this may have changed since I last booked mileage flights for 2019.

My impression is the same as Jules's: At some point in the last few years at least some airlines changed the way they price one-way transatlantic flights. I just spot-checked United's fares between Washington-Dulles and Barcelona outbound in late April and returning in early July. There didn't seem to be a fare penalty for buying one-way tickets. Then I tried a multi-city flight for the same time period, into Barcelona and out of Copenhagen. Again, there wasn't anything odd about the prices of the one-way tickets. I would speculate that the market success (if not financial success) of budget transatlantic carriers might have influenced the shift to this pricing model by the legacy carriers, but I'm only guessing.

Also for United Airlines, one-way frequent-flier tickets cost half as many miles as round-trip tickets. That has been the case at least since 2015. I find that very helpful, because it means I don't have to guess my departure date or departure city so far in advance.

Whether one risks becoming a target for the Security guys when traveling on a one-way ticket, I don't know, but it's a risk I'm willing to take.

@Agnes, Icelandair prices by oneway tickets. The Delta flights I've looked at of late, the one-ways equaled the round trip.

@CWSocial, that is an excellent point. For the most part, I've been buying changeable tickets or with miles, but I do occasionally buy the economy and there I'd be at the mercy of the airline if I needed to cancel a one-way when the associated one-way was substantively changed. I don't want to sound like a Delta commercial because often they really annoy me, but typically, in the end, they've done right by me. Since I have kids across the country, I typically am very able to use my credits. Also, if something were to happen like COVID, earthquake or hurricane, airlines often cancel the flights themselves. I have had flights cancelled due to both hurricanes and COVID.

Just to be clear, I would never trust that the roundtrip is the sum of the one-ways, I'd always double check.

I've been some multicity trips of late. For example, when I went to Honolulu this fall, I stopped in Seattle for a week. I typically end up layover there anyway. I was very surprised to see that the multicity ticket adding Seattle was just $20 more than a round trip ticket to Honolulu. When I price these tickets out, I look at each leg individually to determine the cheapest days to travel.