OGDN311

We are booked on an NCL cruise that offers free air for 2 nd person. Sounded like a great deal until I received an updated invoice charging $1700+ for a RT flight from LAX to Athens, Greece. They won’t be booking the flight for several months and yet the quoted this high price. When I looked I found flights under $700 plus taxes. Am I missing something here or are they trying to pull a fast one?