Terminating flight at layover city

No, not according to the airline rules. Your ticket is legally a contract with the airline to carry you to Frankfurt, not Munich. If this is a round-trip ticket, they may cancel your return home because you breached their rules. I think you probably suspected this, hence the question.

About the only leg you can get away with skipping is the last leg. Skip it in the middle you become a no show and the balance of your ticket/reservation is canceled.

Read Agnes' reply again. It is virtually certain that your return flight will be cancelled and not refundable. I would buy a return on another airline so they can't match you up and penalize you.

I would say that it is considered ethical, and was once a widespread practice, many years ago. After all, you paid for the entire trip and only used part of it. No one gives you a refund if you step off a bus early. I think improvements in software have made the current level of enforcement possible.

It's called 'hidden city ticketing' and I'll add to the consensus that there's a 99% chance that the rest of the ticket gets cancelled after you skip one leg.

Is it allowed, and ethical, to leave a flight at a layover city?

allowed and ethical are two different questions. Is it unethical to not finish a soft drink you bought? Not many people would think so. When you purchase transportation on an airline I don't see any difference between not boarding for another leg and not finishing a can of Coke. You bought the whole journey and if you only take a part of it, that's your choice.

Allowed is a different story. Airlines prohibit this. On routes with competition the prices tend to be lower, so to prevent people from doing the hidden city trick they will cancel any subsequent flight on that ticket. So if you want to do this you will need to book your return trip on another one-way ticket, ideally on a different airline. See https://en.wikipedia.org/wiki/Airline_booking_ploys

As you've been told, it's a no-no.

Also keep this in mind; you bought a ticket to Frankfurt. The airline is obligated to fly you to Frankfurt. They could change your flight and have you make a connection in Berlin or Hamburg or anywhere else.

As always, great advice. Thanks so much.

If you do it on a one way flight, it would work.
But if is the first half of a round trip, your second flight will be cancelled if they catch you.

As always, great advice. Thanks so much.

One more thing to keep in mind. Not only will your return itinerary be cancelled but some airlines will charge your credit card the difference in air fares PLUS a punitive fine if you are caught dumping a leg of your trip. American Airlines has done this. Be warned.

I don’t believe the part about the fine in the story.

Whatever you choose to believe, that's up to you. So what? I wouldn't mention an airline, in this case, American Airlines, unless I knew about it personally. It happened to my brother several years ago. You can also choose not to believe that I have a brother either! :-)

It may have happen, but it is not very common. If it was, there would be a lot of postings on that subjects. Never heard of a fine or even a charge on the credit card. So pay cash.

So in Oct I had the following flights. Orlando-Atlanta- London. London-Atlanta-Orlando

I live in Atlanta. I booked a cheap Southwesr fare to Orlando and got on the plane. Coming back, I got off the plane in Atlanta and headed home. I did not fly the last leg. As of today, around 3 months later no one from the airline has chased me down to bill me :)

I follow a lot of travel message boards and used to fly weekly. Skip the last leg every week or even every month they might bill you. Once a year? Nope. (AMerican is the most aggressive and even then they are looking for a pattern)

Note. Only try this with carry on luggage

I wondered this myself. What about heightened security and someone not being on a connecting flight? (but then lots of people miss connections--due to sickness, time constraints, etc.)

Security only shows up if your luggage gets on a plane without you. And for domestic US flights they don’t match bags to passengers. (After all the checked bags were “screened”)