My wife and I are planning to trip to Vietnam early next year. A number of flights connect through Korea and my wife, being Korean, would like to visit for a few days. Is there a way to extend the normal 4 hour layover in Incheon to 4 days without incurring additional costs? I tried to set up itineraries on Kayak.com with and without the 4 day layover and the price difference was $500. All we are doing is changing the day of the second segment of our flight so I'm not sure why it should be so expensive. Any advice?

Most airlines will allow a 2 day layover on your itinerary for no extra charge. This is a time when it pays to call the airlines directly and find out what the rules are.

I called Korean Air and apparently they do charge for a "stopover". There is no free day allowance unfortunately.

Too bad... have you checked Asiana?

it might be worth the charge if it is not toooo much

That price difference is too high (I think) to be a stopover fee. In the fare rules for any ticket you will see provisions for stopovers, whether or not they are permitted (and how many) and if there is a fee or not. The stopover fees are in the $50 to $100 range.

Here are the stopover rules for fare code KHX3M on Asiana.

3 FREE STOPOVERS PERMITTED AT THE GATEWAY IN LAX/SFO/SEA/ NYC/SEL/CHI. AND - UNLIMITED STOPOVERS PERMITTED AT USD 75.00 EACH. CHILD/INFANT DISCOUNTS APPLY.

I got that info via itasoftware.com

Where are you leaving from Gumbo?

THe reason for the cost hike is that if you stay for 4 days, then it is no longer a "layover", but an open jaw ticket. MRWUNRFL is right, you have to look at at the fare rules of the ticket. My guess is that the price hike is because you are trying to do an open jaw from another Asian hub.

I love itasoftware for these types of routings.