Who could be behind hoax bomb threats to European air travel?

In nearly all cases - London's Heathrow airport being a notable exception - they were taken to be credible enough to divert the aircraft in question, or even in Italy's case, to scramble fighter jets to escort it. It is hardly surprising that the simultaneous, co-ordinated nature of these airline hoaxes, coupled with other malicious actions across Europe, are causing some people to point the finger of suspicion at Russia.

Moscow is certainly furious with Nato for supporting Ukraine and, in doing so, frustrating the Kremlin's plans to swallow up that country and effectively terminate its independence. Russian bloggers have also suggested that, if Ukraine's drones are currently making Russia's airports unsafe, and Western sanctions are blocking Russian airlines from European airspace, then why shouldn't Western nations feel the same pain?

But as of Thursday evening no hard evidence had emerged linking the airline hoaxes to Russia, Iran or any proxy groups controlled by them.