Shorts a no no? Absolutely Absurd. Comfort is paramount. One should wear shorts if one feels it is more comfortable, esp on long haul. I fly J and plenty of diversity on how people dress for flights. For myself, I usually am in jeans and a shirt, then change into shorts and a t-shirt as I get ready for shut eye. SQ keeps its cabins a bit too warm for my comfort, so shorts are always more comfortable.