Here's a worrisome situation: Passenger jet pilots in parts of Eastern Europe and the Middle East are coping with cyberattacks on planes' navigation systems. The digital attacks can jam Global Positioning System (GPS) devices or spoof the signals, making aircraft appear at false locations on maps. It's apparently an effort to confuse incoming drones or missiles, but the disruptions can cause uncertainty and potential risks for civilian aircraft. Affected areas are in the Baltic Sea region or nearby (Germany, Poland, Finland, Sweden, Cyprus, Estonia, Latvia and Lithuania) and in war zones around Ukraine and Israel. No widespread incidents are reported in the United States.

GPS signals from satellites have largely replaced expensive ground devices that transmit radio beams to guide planes toward landing. Crews have backup navigation tools and can contact human air traffic controllers. No accidents are linked to the mischief, though two Finnair planes last April aborted arrivals in Tartu, Estonia, and returned to Helsinki because of GPS interference. The airline suspended landings there for a month.

"Troubling data shows a significant spike in GPS spoofing over the last few months, with an increasing impact on flight safety," says a 9,000-member aviation forum called the OPS Group. (The initials are shorthand for operations.) "On some days, as many as 1,350 flights have encountered spoofing," added the publicly posted advisory last summer.

Pilots experience false ground-height warnings, unexpected flight path deviations and even sudden clock resets -- interference that shows the vulnerability of electronic navigation systems. The increase in incidents coincides partly with Russia's full-scale war in Ukraine and Israel's attacks in the Gaza Strip since last October. Disrupting GPS is an effort to limit the operation of drones. "It cannot be ruled out that this jamming is a form of hybrid warfare with the aim of creating uncertainty and unrest," says Jimmie Adamsson, public affairs chief for the Swedish Navy. An airline industry task force seeks solutions, but hasn't suggested any yet.

Official says: "A growing threat situation must be expected in connection with GPS jamming." -- Joe Wagner of Germany's Federal Office for Information Security

Industry forum says: "Shifts in safety risk are happening without much attention . . . [and] will become painfully clear when the first accident attributable to spoofing occurs." – OPS Group

British specialist says: "Is it going to make a plane crash? No, it's not. It just creates a little confusion. And you run the risk of starting what we call a cascade of events, where something minor happens, something else minor happens and then something serious happens." -- Ken Munro, cybersecurity firm founder