Flights across Greece were cancelled, delayed, or temporarily suspended after a major technical failure disrupted air-traffic control radio communications, prompting authorities to restrict operations as a safety precaution. Greek officials described the incident as “unprecedented,” as controllers struggled to communicate with aircraft across large parts of the country’s airspace.
The disruption began on Sunday, January 4, 2026, around 7:00 a.m. GMT (about 9:00 a.m. local time), when widespread interference affected aviation radio frequencies used for air-traffic communications.
At Athens International Airport (Eleftherios Venizelos), passengers faced long queues as multiple domestic and international flights were held. Airport officials said no aircraft landed or departed for at least two hours during the peak of the outage.
With communications impaired, some inbound flights were diverted to nearby countries, including Türkiye, as contingency measures were put in place.
Air traffic controller representatives called the failure “very serious,” arguing it highlighted the need to modernize equipment and infrastructure. The disruption was linked to problems impacting key control centres, including Athens and Macedonia, which manage large portions of Greek airspace.
Officials said flight safety was maintained throughout, and a government spokesperson stated there was no indication of a cyberattack at this stage, though investigations were launched to determine the cause.
By late morning and into the afternoon, services began resuming progressively as backup solutions were applied and capacity was restored, easing the immediate backlog—though delays continued to ripple across schedules.