Yes and no. The traditional barrier-to-entry for homemade chemical weapons or explosives is that the wannabe terrorist usually ends up killing themselves. That

Yes and no. The traditional barrier-to-entry for homemade chemical weapons or explosives is that the wannabe terrorist usually ends up killing themselves. That doesn't necessarily hold with drones, depending on what the payload is. You might not even need a payload if your plan is just to ram an airliner. So the threat of drones is much higher than "conventional" terrorism IMO.