Flying is safe; far safer than many other modes of transport. However, aeroplanes are increasingly connected and consume data from multiple sources. We've been carrying out independent research into aviation cyber security for several years and have found some interesting vulnerabilities along the way. We'll look at some issues we've found in in-flight entertainment systems and electronic flight bags & the challenges we've had getting these resolved. Some of these could affect flight safety. Fortunately, many aviation technology vendors have been very proactive at fixing bugs, but not all. Is it really possible to hack a plane and how do we go about mitigating security issues? What can we learn on the ground from vulnerabilities in the air?