Steph - hope the boys didn't take flight with that too! Maybe if you replace it, and put some vent flaps in the top to take upward pressure off the canopy? I know boat shops sell plastic scoops to use as vents.
Whew - I'm glad none of your cars or trailer was hit by it. This reminds me of camping in Ellensburg last spring. The winds hit at 0200, and I felt the whole trailer rock. I was able to put my awning back in time, just to see the neighbors tent take off OVER our trailer and land a campsite away. They woke up pretty fast!!
I guess their ground cover wasn't connected to the tent in any way!