I'd say 2% is a whole lot for a single industry, but there's a few more things that make this concerning.
It's an industry that has been growing a lot. It is an industry that is very unevenly used by the world population (many people don't fly at all). And it's an industry that barely has any idea how to fix its emission problem. (H2 will likely only work in short range and is still decades away, synfuels is extremely inefficient.)
We should really get started developing alternatives. Cement is a tough one, probably the toughest industry sector at all. For steel the swedish companies SSAB+LKAB have a very ambitious plan using hydrogen. I hope they succeed doing that.
That said and as othes have noted: Aviation is 2% of CO2, but a much larger share of overall emissions. I was surprised to recently learn that this is scientifically underresearched (particularly effects on cloud formation) and it may be everything between 4 and 7%.
It's an industry that has been growing a lot. It is an industry that is very unevenly used by the world population (many people don't fly at all). And it's an industry that barely has any idea how to fix its emission problem. (H2 will likely only work in short range and is still decades away, synfuels is extremely inefficient.)