In this issue of Advanced Materials in Aerospace Applications IV, we will look at the advancements made since our last issue, published in 2012. Our environment is given increased thought and attention by today's society, and a greener, more sustainable engineering has been the predominant ideology. The use of composite materials has reduced aircraft weight, and has reduced the need for heavy fasteners and joints. This has lead to a more natural laminar flow, and most importantly, better fuel consumption. The aircraft industry relies heavily on composite materials and lightning strikes pose a big risk as composites tend to be inert. Research has been conducted to develop electrically conductive epoxy resins with graphene for the prevention of damage caused from lightning strikes. Finally, we will look at hexavalent chromium's subsequent ban in Europe and what researchers have developed in response.