Lithuania suspended air traffic at Vilnius Airport overnight due to sightings of balloons in its airspace, with flights diverted to neighbouring countries.
Due to a "series of balloons heading toward" the airport, incoming flights were directed to Latvia and Poland while departures were cancelled, the airport operator said on Sunday morning.
One flight arriving from Copenhagen had returned to Denmark.
The airspace reopened at 4.50am local time after several hours of suspension.
It comes after weeks of chaos for European aviation caused by mysterious drone sightings and air incursions, including at airports in Germany, Denmark, Norway and Poland.
Munich Airport closed twice in 24 hours due to drone sightings, only reopening on Saturday morning, according to the Associated Press.
The closures in Munich impacted about 9,500 passengers, with camp beds, drinks and snacks provided to those affected.
Drones were also spotted in Belgium above a military base over the weekend.
A drone incident in Oslo, the capital of Norway, which is a NATO member but not part of the EU, also affected flights there late last month.
NATO member Lithuania in August declared a 90-kilometre no-fly zone parallel to the border with Belarus in response to drones entering from there, saying this would allow its armed forces to react to violations.
Lithuania, a strong supporter of Ukraine, shares a 679km border with Belarus, a close ally of Russia.
The capital Vilnius lies roughly 30km from the border.
Who's responsible for the drones?
It is not clear who has been behind the flyovers.
German authorities were not immediately able to provide any information on who was responsible for the overflights in Munich, with the drones flying away before they could be identified.
European authorities have expressed concerns that they are being carried out by Russia, though some experts have noted that anybody with drones could be behind them.
Russian authorities have rejected claims of involvement, including in recent drone incidents in Denmark.
Last week, drones flew over four Danish airports, which the country's Defence Minister Troels Lund Poulsen labelled a "hybrid attack" from a "professional actor".
What do the flyovers mean?
The drone sightings in Denmark, as well as high-profile aerial incursions by Moscow in Estonia and Poland, have heightened fears that Russia's assault on Ukraine could spill over Europe's borders.
Ukraine's President Volodymyr Zelensky warned Europe on Thursday that the recent drone incursions showed Moscow was looking to "escalate" its aggression.
But Germany's Interior Minister Alexander Dobrindt on Saturday cautioned the public that not every drone was a threat.
He said even if a drone flight was initiated by a foreign power, it did not mean people were in danger, saying the flyover could be a provocation.
Mr Dobrindt also said Berlin needed to "find new responses to this hybrid threat" — including potentially shooting down the drones.
Moscow said it "firmly rejects" any suggestion of involvement, with Russian President Vladimir Putin accusing Europe of stoking "hysteria" to justify rising military spending.
Reuters/AP/AFP
