The MacBook Air comes with a dual-core 8th-generation Intel chip, and you can't upgrade to a more powerful chip with four cores.
The cheaper MacBook Pros from 2017 come with Intel's 7th-generation dual-core Core i5 chips. You can upgrade to a more powerful dual-core Core i7.
The recent 2018 MacBook Pros come with Intel's 8th-generation quad-core Core i5 chips as standard, and can be upgraded to quad-core Core i7 chips.
It's hard to tell whether the new MacBook Airs are as powerful as the 2017 MacBook Pros. It's pretty much a guarantee that the 2018 MacBook Pros are more powerful than the new MacBook Airs, but we'll still need to wait for thorough testing to know for sure.
However, the new MacBook Air seems to hold its own. YouTuber Kraig Adams told 9to5Mac that the new MacBook Air could absolutely be his primary editing machine after testing it out.