On Thursday and Friday, two Finnair flights from Helsinki to the Estonian city of Tartu were forced by the GPS jamming to turn around and return to Finland as they were unable to navigate safely to their planned destination. https://www.ft.com/content/37776b16-0b92-4a23-9f90-199d45d955c3
Russian GPS jamming threatens air disaster, warn Baltic ministers

Interference with navigation signals blamed on Moscow has forced two Finnish flights to turn around mid-journey

@LukaszOleall airliners have inertial navigation because of GPS jamming. Before GPS this was the main way in planes and only way in submarines
@JohnLoader6 I have some small experience with both inertial navigation systems and VOR navigation in aircraft but am not a pilot nor do I know airliners. In the absence of GPS I think I would rather rely primarily on VORs because inertial systems accumulate error. Having said that, maybe you can't use VORs in the affected areas (they need ground-based beacons). Anyway, having both available would be fantastic.