He doesn't. That's kind of the thing. If it were up to me, FSonic's abilities would just be integrated into normal sonic, and he gains a couple of extra stuff too like a jumpswitch (is that what it's called?) and a peelout. The thok works, but sonic needs more benefits than just Thok and elemental shield use. He felt more lacking compared to the other characters, but not just because "oh he doesn't have any good vertical movement". Tails and Knuckles completely dominate in vertical movement, so i feel that sonic should dominate in horizontal too.