it goes into an engine. it could take out an engine. if it goes into a cockpit window it would injure or kill a pilot. it's happening more and more. >> is there any way to detect them? i don't want to be on an airplane and -- how can you tell if a drone is close by? >> a lot of it is eyesight. pilots are aware of what's going on when you're going toward critical phases of takeoff or landing they're looking out the windows while monitoring the systems. they're keeping a close eye out there. it's difficult. a lot of these are the size of this table, maybe smaller, some are larger. it's a challenge out there for them. >> this bulletin alarming because it's saying obviously terrorists are watching what's happening. and if hobbyists can do it, terrorists could easily get their hands on a drone and the way you're describing this unless the pilot can see it with eyesight it could potentially bring down a flight. >> there is a danger. i'm much more concerned about people that are being careless with these. i'm not too nervous about the terror suspect yet because the careless part is out there and so prevalent these days. >> is there any way to stop it?