The warnings followed separate threats on Tuesday and Thursday that forced at least 35 flights to be diverted or searched. That sequence raised questions over an apparently coordinated effort to cause chaos for travellers.
A separate spate of threats on Friday against media organisations in Ireland disrupted broadcasts. Staff were evacuated and police searched offices and newsrooms.
A fresh wave of bomb threats disrupted air traffic across Europe on Friday. Affected aircraft landed safely and searches found no explosive devices.
“It cannot be mere coincidence that so many incidents with exactly the same modus operandi are happening across Europe,” a speaker told the national broadcaster TVE.
The flights hit on Friday had knock-on effects but were a tiny share of traffic. They amounted to 0.0674 percent of the 26,709 flights Eurocontrol said were scheduled in Europe that day. Martin said the episode showed how relatively simple it can be to cause disruption and undermine the normal operation of society. He added that European security agencies would seek to identify those responsible and hold them accountable.
“The most reasonable assumption is that we are facing an attempt at hybrid aggression and a form of psychological warfare,” he said, adding that Europe must be prepared for more such challenges. The British broadcaster Sky said on Friday it had also received a security threat and reported the matter to the relevant authorities.