I have always wondered about drag or reduced gas mileage with destroyed under carriage plastic covering. I have often repaired mine by removing completely or zip ties. Recently once again my car, 2006 Buick Lucerne, experienced damage on the front underneath black plastic covering. I repaired with 4 zip ties securely. Two on the sides and two on the front.
What's your recommendation when this happens. Remove or repair. Note, My damage is not terrible but did gash open the protection a bit. This buick also has a frame which appears coated or aluminum.
Remove it and put it in a dark corner of your garage. It is useless, no matter what you're told.
One day when I went to do an oil change the plastic crap under my car was gone. It must have fallen out in the road somewhere and I hadn't even noticed. Still don't notice it.
Remove
Cables ties are a valid, respectable, certified repair 🙂 I often employ them as well.
They are right up there with electrical tape, pop rivets, bungee straps, sheet metal screws, caulking and primer paint
What about Bondo, Duck Tape and my wife's panty hose as a paint strainer?
Bondo is too fancy for me.
Duct tape is ok for very temporary use. Leave it too long and the sunlight will turn it into an even bigger chore.
I see your pantyhose, and raise you old underwear shop rags.
Sees both your undergarments & raise you old tees & blankets cut into hand towels as all purpose rags. Also, gaffa tape/speed tape -

That should hold it together until next service!