http://www.dailymail.co.uk/news/article-3348064/Drone-attacks-airliners-biggest-risk-posed-unmanned-aircraft-warns-anti-terror-expert.html
- Defence specialist Colin Smith said unmanned aircraft endanger passengers
- Officials worry that they could be flown into jet engines and take planes down
- Smith also said they could be used to drag Isis banners at high-profile events
- There are already near misses every week, he said - and demand is rising