Flip flops are beach and beach like activity only. Conversely, a nice, leather sandal is perfectly acceptable, if one takes care of his feet. Everyone's go to suiting brand creator and director Gianluca Isaia agrees.
You don't always have to wear wing tips with suits. In the summer, I wear sandals, handmade in Capri, to make my suits a little less dramatic. As long as you wear something naturally, it can never lose its elegance.