Molotovs are your friend. C-4 and its relatives are friends too. You don't just use those on their own for a pyro; you plant them on gas-lines or use them as the ignition/primary form of deployment for the device. It exploding and spraying a 55 gallon drum of styrofoam soaked in bio-diesel all over is going to ruin
someone's day. Probably multiple someones, to be frank.
By definition, space begins at about 100km, therefore we aren't talking about mana voids.
And I think you are severely overestimating the ability of a drone to carry a 1000kg weight into an area with about 0.16% of sea level air pressure.
Finally: 50km x 1000kg x 9.81g = 490.5 MJ ~ 110 kg of TNT
That's a lot, but not so much that you'd create an international incident - depending on your target and it's location you wouldn't even make the news, since you didn't actually use explosives but a meteor. Getting caught after the fact should be very, very hard to do if the drone was wireless off during the hit.
It'll still be a severe Ebb. That Ebb will suck Force from the spell until you can't support it any more. Force 5 can lift a 1,000 kilo hunk of metal. Let's say 50km is a Mana Ebb of -7, as it's half-way between the ground and the Void that is space. You'll have to cast the spell at Force 12 to get it up there, if you're lucky.
This also doesn't factor in the fact that Levitate only lifts the item by (Force) meters per Combat Turn. So, assuming a 3-5 second Combat Turn and the minimum Force because we won't factor in the Ebb, you've got an ascent of 60m to 100m a minute. 6kmph on the quick side is going to take you over eight hours of constantly lifting the thing; longer if we go with the longer Combat Turn. And everybody and their pet spirit will probably notice the floating spell going up and up and up into the sky, hefting a makeshift meteor.
I'm still not sure how you're going to target this drone if the Wireless is off; you have to communicate with it too. This doesn't even factor in possible signal issues.
How many people in the world have been struck by meteors? I think the current count in recorded history is
1. And they didn't die. Someone getting hit by a meteor is going to get noticed out of novelty, if nothing else. And when they examine the projectile and find it was actually a steel rod stolen from a construction site/manufacturing plant (which they could figure out by the composition)... Yeah, fat chance a stunt like this isn't investigated. You'd be better off sabotaging an actual launch and directing the falling craft at the target, with the hopes that you either covered your tracks really well or set up someone else for the fall.
Finally, drone is a very loose term. You could call an unmanned rocket a drone, which you could launch that height without a payload and drop on the head of your target just as easily. Probably a better option than using magic.
