What are the differences between big air and slopestyle snowboarding?
A typical slopestyle course features three rail sections and three jump sections. Take one of those jump sections, make it larger, and you basically have big air.
Aside from that, the biggest difference is in the competition format. Slopestyle forces riders to put together one well-rounded run, while big air only requires riders to land one trick at a time but still emphasizes consistency and variety due to its best-two-of-three format.
The skills used for slopestyle and big air largely are transferrable, so athletes who qualify will compete in both at the Winter Olympics. However, there are many athletes who specialize in one more so than the other.