First of all, I took off in the first round and began casting in the second. It was at the end of the second round that I got hit by the sling.
6 ranks in both Flying and Endurance. We were level 1.
My stamina RR was low against the stun. Being stunned applies a 50 point penalty to all subsequent actions. That, plus the 10 point penalty from the sling (doubled to 20, since it's an entry on the crushing table that specifically mentions broken bones) meant I had a 70 point penalty when I made a Flying maneuver to stay airborne. With that big a penalty, rolling poorly and therefore getting well below 0 on a Flying maneuver was what one could expect.
Ergo, I fell.
By that point, I'd already placed my miniature over the river, which was below us in the gorge, in order to be out of range of the brigands advancing across the rickety rope bridge with swords, but no bows in sight. Getting hit by a brigand who also happened to have a sling was surprising, to say the least.
But I digress.
The point is, being over the gorge meant I fell over a hundred feet, which in and of itself is a large crushing critical. Hollow bones bumps that up to huge, and when the GM rolled the damage roll, he rolled in the 96-100 range.
Twice.
What's the result on the critical table for when OB is more than 280 points above the effective DB? Instant death.
Ergo, I smashed into the ground, dying instantly on impact. So yes, I got hit with a planet, thanks to the attack roll made by gravity (that's how the falling rules work).
For the record, your post is the first I'd heard of fate points. Even after playing several sessions after the one in question, nobody has ever used any, nor mentioned using them. I don't know if our GM even allows fate points.