In the 1480s, Leonardo da Vinci drew over 100 illustrations that constituted the first real studies on human flight. One of these, a pen-and-ink sketch of a flying machine similar to a modern helicopter, contained what da Vinci called an ‘aerial screw’ – perhaps the first true aircraft fastener type, similar to a water screw but working in the air instead of water. Fast forward 541 years and the number of domestic and global airline flights worldwide is an estimated 22.2 million (in 2021). And with the demand for more affordable flights, the aerospace industry is growing at a rapid pace – and with it, the need for more specialised aircraft fastener types. The number of aircraft fasteners (bolt or screws, rivets,
