Nato member Lithuania closed its capital airport late on Saturday and shut both crossings on the border with Belarus after helium weather balloons drifted into the Baltic country's territory for a second consecutive day.
Traffic at Vilnius Airport was suspended until 2am, while the Belarus border will remain shut until the same time, Lithuanian officials said.
European aviation has repeatedly been thrown into chaos in recent weeks by drone sightings and other air incursions, including at airports in Copenhagen, Munich and the Baltic region.
The Vilnius airport also closed on Tuesday and Friday of this week and on October 5, each time due to balloons entering the capital's airspace, authorities have said.
Lithuania has said balloons are sent by smugglers transporting contraband cigarettes, but it also blames Belarus president Alexander Lukashenko, a close ally of Russian president Vladimir Putin, for not stopping the practice.
Lithuanian Prime Minister Inga Ruginiene on Friday said the country's National Security Commission will meet next week to assess the situation.
