If you don’t know what an open-jaw itinerary is and haven’t booked flights this way, you’re not alone. The simplest way to think about an open jaw is that it represents a gap without flights at some point in an itinerary. A common use is for two-way travel on an itinerary where the destination and/or the origin cities aren’t the same in both directions. An example of an open-jaw itinerary with flights from Chicago (ORD) to Paris (CDG) and Madrid (MAD) to Chicago is depicted below. The...