Agree @FourNinesCasual nights my husband will wear a short sleeve button down or long sleeve button down with his pants, on dressier nights he adds a sport coat. Last year one night after dinner (with a sport coat) a crew member passed us in the hallway and said to my husband "looing good there my man" so I do think the crew appreciates alittle effort these days of jeans and shorts for dinner and after dinner. Pretty funny considering the memories of tuxes and full suits and ties. It has changed the ambiance over the decades, but it does make the travel easier no question about it.