So there's one feature the Air is missing according to a deep dive of the Compare sheet (https://www.apple.com/iphone/compare/): The Air does not support mmWave cellular connectivity, while the other models (and previous models going back awhile) do support it.
That is...weird? Why would the Air's design prevent that?
The mmWave functionality requires a glass section on the frame as it can't pass through metals. They've redesigned this on the 17 Pro[1], but likely didn't find a way to integrate into the Air's design.
When Camera Control was introduced on iPhone 16, Apple moved the 5G mmWave antenna to pass through the back glass of the iPhone, that way it was no longer something you needed to see.
Now though, with iPhone 17 Pro – that can’t work. The iPhone is now largely made of aluminum, requiring Apple to revert to an old design technique: a glass cutout for 5G mmWave passthrough
I remember having ~150Mbps with an iPhone 8 on LTE in 2017. Bandwidth itself has basically never been the limiting factor for the last decade or so. The problem is always data caps, and unless 5G/mmWave/etc is somehow magically exempt, it's not really a benefit (you can now burn through your monthly quota in seconds instead of minutes - great!).
I talked to ChatGPT about it for a while. It says mmWave means you can get 1-3gbps speeds if you're in a covered area. However, most are stadiums, airports, etc.. Verizon has by far the largest coverage, then AT&T.
At least in my daily use, it means nothing. I've also never seen speeds like that when I've tested the phone.
That is...weird? Why would the Air's design prevent that?