Where are they cheapest to book? I want to fly to the US next summer (for the first time in ages ) Initially, I want to get to Charlotte, NC, but Charlotte is basically the most expensive airport to fly into, internationally and a flight into Boston costs oh 400â‚¬ less. So I want to fly into Boston, visit some Rhode Island friends and then take an inland flight down to Charlotte, which costs somewhere between $130 and $200. I have no idea where its best to book though. I usually book through expedia.de, but their inland flights in the US are far more expensive than the same flight on expedia.com.