From the end of the article: "There are many ways of coordinating an attack without using a mobile phone," says Aurélie Branchereau-Giles of OnAir, a company b

From the end of the article: "There are many ways of coordinating an attack without using a mobile phone," says Aurélie Branchereau-Giles of OnAir, a company based in Geneva, Switzerland, that Airbus is backing as a maker of in-flight cellphone and Wi-Fi systems. "The position of our security experts is that the use of mobile phones on planes does not constitute any additional security threat." I tend to agree. A timer is as effective, though perhaps slightly less precise, than a phone call. Even as it stands, one could probably set up an ad-hoc network with the explosives (laptop in luggage? Not sure about signal strength.) and use pretty much any electronic device to connect to it.