By Beth Hardie You may want to rethink your favourite flight clothes if you don’t want to risk getting it soiled and picking up germs. The well known adage ‘you should never judge a book by a cover’ doesn’t really apply when it comes to travel, if one flight attendant’s observations are anything to go by. She reckons she’s sussed out what category people fall into depending on what they choose to wear on a plane. It probably didn’t enter your mind that anyone would judge you based on your tracksuit bottoms and sweatshirt or your little summer dress you popped on, thinking it would be nice and …