All Amazon Flex delivery drivers are independent contractors. It's not much different from driving for Uber. My last Amazon package was delivered by a 21 year old in a t-shirt and jeans driving an old Nissan sedan.

https://flex.amazon.com/

And they hire independent delivery companies (who themselves can hire contractors to work for them) as well.

https://logistics.amazon.com/

I was curious about where Amazon Flex delivered so I went to their site. No indication of whether my area was covered or not so I ended up downloading the app. Once signed in the only location listed was Pennsylvania. Not where I live so instant delete. Not sure why they didn't just put that on the landing page.