I only travel for tourism, and I only take cabin luggage; I wear whatever it is I will be wearing on location: jeans/comfortable trousers, comfortable shoes/sneakers/boots (depending on weather), tops also depend on weather.
I've never been on a flight longer than 3h though so that might explain why I've never thought of this before.
I've never been on a flight longer than 3h though so that might explain why I've never thought of this before.