On many long-haul flights where sleeping is expected the airlines will provide pajamas to their first-class passengers.

Flying used to be special and something that very few people did and, as a result, people often dressed up for their flights. Today, flying is often seen as a chore and just a convenient way of getting from one place to another. We've gone from planes that seated much fewer people where real meals with silverware were served to massive planes where one is often served out of a cardboard box.

If first-class passengers are walking around in pajamas, I wouldn't worry too much about sweatpants anywhere else on the flight. No matter where you are someone will have an opinion on how you're dressed. I would personally find sweatpants to be too hot for a long flight but it's your comfort that matters.

On many long-haul flights where sleeping is expected the airlines will provide pajamas to their first-class passengers.

Flying used to be special and something that very few people did and, as a result, people often dressed up for their flights. Today, flying is often seen as a chore and just a convenient way of getting from one place to another. We've gone from planes that seated many fewer people where real meals with silverware were served to massive planes where one is often served out of a cardboard box.

If first-class passengers are walking around in pajamas, I wouldn't worry too much about sweatpants anywhere else on the flight. No matter where you are someone will have an opinion on how you're dressed. I would personally find sweatpants to be too hot for a long flight but it's your comfort that matters.