I want to book a round trip ticket (for travel within Europe) and use only the first leg of the ticket (because it's cheaper). Can I do that without getting in trouble with the airlines?
you should google "skiplagging" - it violates airline "contract of carriage" and can have some pretty significant consequences...
Ok. Thank you!
We're talking two types of "Throwaway" ticketing.
What the OP it's asking about is "Point-of-Origin" or traditional throwaway. That is purchasing a round-trip ticket and only making the outbound flight.
"Skiplagging" is also hidden-city ticketing. That is buying a ticket from A to C with the intent to terminate on the connection at B.
Two thoughts. First, there are many circumstances in which passengers book round-trip but cannot use the return leg: illness, meetings run too long, car breaks down, etc. Airlines don't have much basis for punishing those who find themselves unable to use the return leg of a no-changes-allowed round-trip ticket.
Second, unless you don't plan to return eventually to your place of origin, you should explore open-leg tickets. They're not usually much more expensive than round-trip booking, and in some cases are cheaper.
VAP is right about the two kinds of “not showing”. I almost always buy round trip or multi-city tickets. Twice I have decided to not use the entire return ticket (change of dates and found a good deal with miles). So I called the airline (AA) and they cancelled that return. That gave me some flight credit instead of just not showing up (admittedly very unuseful credit because of stipulations - but still I could potentially use it). Not a problem. Just call the airline and let them know after you take your outbound flight.
However the type called skip-lagging is where you buy a ticket from A to C, with a stop for plane change in B - when all you really want is A to B. So you just don’t get on the plane B to C. At that point the airline cancels the whole rest of your flight, so you have no return flight. Sometimes the leg you don’t want might be the final flight on your return. You might get by with it - but you might also have a problem the next time you try to book, because this is illegal.
This is a head-snapping rebound in policy but airlines have largely abandoned massive premiums for single segments vs RT. But check pricing on an open-jaws ticket vs the RT+the extra segment back home. You may be surprised that it works just fine financially. Also don't just check your favorite airline even if you love their service/mileage plan.
https://thriftytraveler.com/news/flights/airlines-one-way-fares-international/