titanium.... lol....
there is a reason why cars are made from carbon fiber, and extremely rarely titanium.
First off obtaining the material is a lot more difficult then anything else, as only a few countries export it.
And Tesla logistics is horrible, having them try to source titanium, im sorry id think mold would grow faster in a sterile room then telsa getting replacement panels for titanium.
At least they have a TON of stainless steel for the rockets.
Its not difficult getting more unless the US somehow has a steel storage, which i doubt since we the US has a large surplus of steel.