I read somewhere to wear kinda heavy stuff to save weight in your back plus it can get cold on planes? then get changed at the air port but someone else said were comfortable stuff, light + layers? so..
Depends on where and how far you are going.
It is usually good not to wear too much metal - like shoes with steel caps or metal belts and such - in order to get through the security check fast.
As for clothing. If you start in Brazillian tropical temperatures and go to northern American frosty winter, you should wear something that doesn't get you are heat stroke at origin and that doesn't make you freeze to death instantly upon arrival. Several layers would be recommendable.
Plane air conditioning is usually set to low room temperature. Around 20° celsius / 68° farenheit. Wear something that makes you feel comfortable at that temperature. If you have a rather heavy mantle, you can wear it during check-in in order to decrease the weight of your luggage. If it gets too warm during the flight you can just place it in the abovehead flap with the carry-on luggage.
My general rule for flying, wear something light and comfy, wearr a singlet under whatever you're wearing just in case it gets hot, and bring a cardigan just in case it gets cold. Wear comfy shoes and you'll be all good.
if its a.long plane trip i would wear pj's. And change to normal clothes when you get to the hotel or wherever you are staying
Sweatpants or jeans, tank top, and a sweater. Just be comfy.
Something comfyyy (: Like sweatpants & a shirt.