Do MacBooks have scissor-switch keyboards yet (Feb 2020)? I can't get a clear answer about this topic. According to the live chat support on the Apple Store website, the mid-2019 MacBook Air models do have the scissor-switch keyboard. However, every other source I check says they still have the butterfly keyboards until mid-2020.

Can I get a definitive answer about whether a new MacBook purchase in the US would have the previous butterfly style keyboard or the newly planned scissor-switch keyboard?
The 2019 MacBook Air uses the third-generation Butterfly keyboard.

This is also clearly stated on Apple's marketing page for the 2019 MacBook Air: 


  "The latest-generation MacBook Air keyboard features our butterfly mechanism [...]"


The new scissor-switch style keyboard debuted on the 16" MacBook Pro, which was released in November of 2019. The 2019 MacBook Air is from July of 2019.

It doesn't matter which country you buy your MacBook Air in. Different countries obviously have different keyboard in terms of number of keys and the letters on them - but they're all made in the same way. I.e. a Mid 2019 MacBook Air is going to have the same style of keyboard in every country.

There's no such thing as a "Mid 2020 MacBook Air" (yet). You can only speculate whether it will have a scissor-switch key, or the butterfly keyboard. The public does not know.