"Federal officials have long been aware of the possibility that someone might try to use such planes as weapons, but there are no restrictions on their purchase -- Ferdaus is said to have bought his on the Internet.
Counterterrorism experts and model-aircraft hobbyists said it would be nearly impossible to inflict large-scale damage of the sort Ferdaus allegedly envisioned using model planes. The aircraft are too small, can't carry enough explosives and are too tricky to fly, they said."
Read the rest of the news article in "Model planes as weapons? Experts blow holes in plot.", The Portland Press Herald, September 30, 2011.