I flew on a Korean Air Boeing 747-8 from Atlanta to Seoul Incheon in First Class. This is the current longest Boeing 747 flight in the world with over 7,100 miles and with 15-16 hours of flying time.

First-class fliers have a code. It’s subtle and usually comes with a glass of champagne. If you want fit in before you fall flat in a sea of stares, learn the unspoken rules—lest you mistake the amuse ...