What to wear on an airplane?

Ok, so tomorrow I am going to be flying from Spokane, WA to Chicago, then from Chicago to Frankfurt, then from Frankfurt to Paris, France. So, I'll be on airplanes/in airports for a reaaally long time (something like 16 hours or more??). Anyways, would it be acceptable to wear VS Pink sweatpants with a hoodie? Its these sweats/hoodie specifically: http://www.victoriassecret.com/ss/Satellite?ProductID=1265500482233&c=Page&cid=1305797379669&pagename=vsdWrapper ( I have the grey colored ones). They are well fitted, not at all baggy, so do you think it'd be ok for me to wear them while traveling? Or should I wear something else? Thanks!