(By more poweful i meant higher frequency (2-3 times) - wrong choice of words :)
Not really. Most mobile phones these day operate on the 1.8GHz band (in Europe). Wi-Fi is on the 2.4GHz band.Unless they can actually prove and/or specifically tell you, I don't see anything wrong with it. Could just be an urban legend that's gotten out of control, and of course people are completely paranoid of flying, even though it's the safest form of travel ever.