BBC News: “Russia is causing disruption to satellite navigation systems affecting thousands of civilian flights, experts say. […] The persistent disruption led Finland’s flag carrier Finnair to suspend daily flights to Estonia’s second largest city, Tartu, for a month, after two of its aircraft had to return to Helsinki due to GPS interference. ¶ Tartu Airport relies solely on GPS, unlike most larger airports which have alternative navigation systems that allow aircraft to land even if the signal is lost.”