Modern Day: A Dragon Scours the Land

[Incanur]

Bear in mind that a modern anti air missile has a kill radius of about 10m. They don't actually need to connect with a target, just get close enough and explode where the shrapnel produced by the warhead and casing shreds the target.

(Also, not effective vs. antiaircraft cannon fire or other large bore weapons, armour piercing rounds not particularly affected by lightning)

Magical lightning (or perhaps high-tech particle beams that mimic lightning) doesn't necessarily care about such issues. Dump enough energy into any projectile and it'll be knocked off course or vaporized. Particle beams travel at nearly the speed of light, so it's theoretically viable in that sense. It would require impressive reflexes for the dragon, however, unless it just generates some sort of electrical field that fries everything in a certain area.