Reports that a cybersecurity expert successfully hacked into an aeroplane’s control system from a passenger seat raises many worrying questions for the airline industry. It was once believed that the cockpit network that allows the pilot to control the plane was fully insulated and separate from the passenger network running the in-flight entertainment system. This should make it impossible for a hacker in a passenger seat to interfere with the course of the flight. But the unfolding story of this hacker’s achievement, which has prompted further investigation by authorities and rebuttals from plane manufacturers, means that this assumption needs to be revisited. In a similar way, it was once also believed that PIN protection was sufficient for ATMs. Then it was discovered that keystroke logging software can be used to translate sound signals created when pressing the ATM numeric keypad into the PIN, greatly reducing the time needed for hackers to guess for it. This could increase the risk of an ATM security breach compared with the previously held assumption that the system is secure as long as nobody can see it. When it comes to technology, as one person is making sure that a system is secure, another is already working to bypass the established security. That is a worrying prospect when you’re at 30,000 feet and travelling at over 500 miles an hour.