I do a lot of long haul flying - many of my business trips are 24 hours plus (door to door). I always wear Juicy on the plane - with a singlet underneath. Planes are either freezing cold or roasting - you need to be prepared for either. I went to NY last week and wore a purple Juicy suit, a purple/pink vintage mohair cape and beige uggs. It doesn't have to look scruffy - wear a bit of trendy jewellery with it and it can look nice.
I've been doing these trips for along time, so I'm quite organised, now.
I find it really hard to sleep in jeans or formal wear - its too restricting - the waistband can feel so uncomfortable when you are trying to sleep and creases terribly. I would never wear make up on a long haul flight - it wrecks your skin. - I always take with me on the flight a blow-up neck pillow, earplugs and an eye mask, also lip balm - a really good moisturiser, wet wipes, and hand cream. I sometimes braid my hair before I fly as the dryness in the cabin tends to make for a hair horror. If you can wash your hair just before you fly that helps too. I usually have tinted brows and lashes, so I can get away with no make up.
Years ago I remember flying back from Hong Kong to London, there was a lady opposite me who was wearing a Versace pencil skirt and very high heels - she looked fab, but so uncomfortable. No one cares what you look like when you fly - save the impressions for when you arrive. You can always change before you leave the airport if you must.
What I really don't like to see is people coming back from vacation (a hot place) to their home country (freezing cold) still wearing their shorts /sandals /sombrero - yes we know you've been away! Aren't you cold?
It looks so trashy
and Tiamaria - I'm yet to visit a lounge which has a dress code -where is that?