I draw planes blowing up crap all the time. Hell, in most classes, I'm in the front row of seats. The teachers sometimes see it, and don't say anything about it.
Anyway, this is really unjustified, as it's just a drawing. Yeah, I guess we should all suspect a teen in school is planning to buy several fighter jets, bombs, and fuel to power them, and to follow the plan he simply thought of fictionally and actually go through with it.
And they say us kids are the "twisted" up generation.