Yes battery tests are positive for the Air with it being pretty close to the regular iPhone 17, despite the smaller battery.
The A19 Pro is more efficient than the A19 and also the C1X modem exclusively in the Air is more power efficient.
A19 Pro + C1X + N1 all Apple designed chips allowing for top level optimisation to achieve these numbers.
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These battery tests, however, due to their heaviness, tend to clump iPhones together. Heavy use kills them far faster, so the results tend to be closer than they are in real life (at least in my experience).
For example, see this test of the iPhone 8 vs the Xʀ, which was made when iOS 13 was the latest:
The iPhone 8 ended with 5h 08 min. The Xʀ, 7h 29 min. So the iPhone 8 lasted almost 70% as much as the Xʀ did. In my experience… it isn’t that close. With efficient usage, I’d say the iPhone 8 gives me about 45-50% of the battery life of the Xʀ, tested practically on their original iOS versions, iOS 12, back in 2021.
Heavy tests make good battery life iPhones worse than what they worsen comparatively poor iPhones. I’ve always been massively skeptical. This is obviously seen with those tests that compare iOS updates. If you kill both versions, it makes the original one look worse in comparison. With lighter usage, the difference skyrockets. I’ve seen this repeatedly, both with iOS version tests, and when testing different iPhones.
That’s why I don’t consider these tests reliable. A more moderate use highlights the difference a LOT better. I’ve always seen this, especially when they compare iPhones that I have personally tested.
Remember this: intensive use is so inefficient that it blurs iPhones together. Twice the battery capacity makes less difference than it should.