If you’re a frequent traveler, you’re already used to paying for a lot of things that were once free. For example, being able to choose your seat, in-flight food, and even the right to a carry-on bag.

Did you know you can fly Ethiopian Airlines from Stockholm to Oslo, a quick 40-minute hop on a 787 Dreamliner? It’s what they call a fifth-freedom flight and it’s pretty fun as an option on this route ...