Each time the wind gusts from the east from Belarus, Lithuania braces for problems.
That is when enormous inflatables are sent across the border, with boxes of cheap cigarettes hanging beneath.
Over the past 10 weeks, this illicit balloon traffic has compelled Lithuania's primary air hub into closure 15 times, delaying thousands of travellers.
On a single instance, the national skies was closed completely for a lengthy 11 hours.
However, the authorities are adamant they are confronting something much more aggressive than simple smugglers.
They assert the balloons have been "weaponised" in an example of covert aggression by Belarus, Russia's closest ally.
State of Alert
The Lithuanian administration has instituted an official alert.
While balloons have been utilized by smugglers before, their numbers escalated rapidly this October.
"Naturally it began as organised crime activity, but we've seen more than once how Belarus exploits organised crime to have an effect on neighbouring countries," a government minister stated.
The official argued the balloons are sent from locations that help them best "target" Lithuania's main airport, situated just 30km from the border.
"If you want to conduct a smuggling operation, you'd do it in the woods or marshes, not directly at our airport!" the minister pointed out.
Instead, there is a view that the balloons represent a form of diplomatic leverage on Europe's eastern edge.
"They see this as leverage: 'You have a border with us, we can cause you {huge problems|significant disruption|major issues'," the official said. "What they're doing is really entering the realm of national security."
Border Vigilance
Now, nightly, military police head out in the border zone.
The balloons are most frequent during the night.
Units establish temporary roadblocks on remote country roads, inspecting drivers' documents and searching vehicles in search of anyone involved to the smuggling networks.
The balloons travel too high to make shooting them down a viable or cost-effective option.
Consequently, the government has offered a €1m prize to any firm that can figure out how to intercept them.
In the meantime, teams use advanced tracking systems to monitor the balloons and attempt to catch smugglers at the landing sites.
Soon, new legal penalties for acts of sabotage should also act as a preventive measure.
Political Objectives
The frontier line is now defined by a high security barrier, with barbed wire and concrete blocks.
This extra security is a clear sign of how Lithuania now considers its neighbour as hostile.
Not far away, the leader of Belarus has dismissed all talk of hybrid warfare as "fabricated".
He recently blamed "bandit" smugglers, saying they were simply seeking a profit and getting creative to overcome the new security fence.
Lithuania does not buy that, partly due to a history of hybrid tactics.
In 2021, migrants were facilitated to cross into Lithuania and Poland in significant quantities, provoking a deliberate crisis.
"Now they are doing a series of one or two balloons every 30 minutes, precisely targeted at the airport," explained a crisis management official.
"{In Belarus... if they were interested in stopping it they could do it tomorrow. But they don't. That means it benefits them."
The prevailing theory is that Belarus is attempting to pressure its way into reducing international restrictions.
"They want to attract political attention and compel us to change our policies towards Belarus," is how one minister interprets the sudden influx of balloons.
The EU has not recognized the Belarusian leader as legitimate following contested votes in 2020 and a subsequent crackdown.
Sanctions were imposed then and strengthened later when Belarus aided Russia's war of Ukraine.
"{First, they want to end the diplomatic ostracism of the regime and secondly, of course, the sanctions," the minister stated.
Public Discontent
For now, travellers and airlines are having to adapt.
"This is something completely new for the aviation sector," stated the airport CEO.
One airline has already moved its charter flights, and another has reduced its evening service.
Revenue losses for all affected businesses are estimated to reach €2m by year's end.
"There are direct financial costs, but the greater concern is if passengers start to lose confidence in air travel," he admitted.
Already, travellers consult a new webpage for wind forecasts and balloon probability before booking flights.
"It's not easy, it makes me a anxious. I'd just like to get home as planned," one passenger said.
"We believe this is a hybrid attack on us," said a local resident. "I think for them it's really funny to fly those balloons and then mock us."
Her words suggest that another aim of such hybrid activity – sowing discontent – is also working, and perhaps harder to defend against.
"They're basically testing the limits of the alliance: looking at how we respond to these kinds of things," said another citizen.
"And we can't even fight simple balloons. We're not even prepared for the fundamental challenges."