This fall, the iPhone lineup is getting a brand new model: the iPhone 17 Air. Apple plans to drop its Plus model in favor of an iPhone with a fresh form factor that could tempt a lot of Pro users. Here are seven features coming to the iPhone 17 Air.Ultra-thin form factorApples ultra-thin M4 iPad Pro gives us an idea of what to expect from iPhone 17 AirFollowing the trend started by Apples M4 iPad Pro, the iPhone 17 Airs defining feature will be its thinness.Reports have varied around the exact measurements of the new device, but most recently, Ming-Chi Kuo wrote that its thinnest part will be just 5.5mm. Presumably, this means everything except the top camera bar.This is a massive reduction from current iPhones. The 16 Pro models are 8.25mm thick, while the base 16 and 16 Plus are 7.8mm.Apples thinnest model ever was the iPhone 6, and even that was 6.9mm.New 6.6-inch displayBeing ultra-thin wont be the 17 Airs only hardware advantage over the Pro line. Apple will also give its new model a unique display that could offer the perfect compromise between existing sizes.Apples iPhone 17 Pro and Pro Max will feature 6.3-inch and 6.9-inch displays, respectively. These are the same sizes as the 16 Pro line.iPhone 17 Air, however, will slot in exactly halfway between the two models with a 6.6-inch display. Thanks to its ultra-thin form factor, the 17 Airs display may still feel small enough for current Pro users while offering just enough space to satisfy Pro Max fans too.Always On and high refresh rate featuresEver since 2022, a big difference between Apples entry models and Pro line has involved two display features:the Pro models boast an Always On displaythey also support the 120Hz ProMotion high refresh rateThese are the kind of features that, once you get used to them, theyre hard to go without.Fortunately, for the first time, Always On and a version of ProMotion are expected to hit the base iPhone 17 and 17 Air.I say a version of because rumors have swirled about a possible 90Hz refresh rate display being in the works at Apple. No credible rumor has indicated this will hit the 17 Air, so its possible it will get the full 120Hz ProMotion feature. But if Apple wants to boost its iPhone displays while still retaining the best tech for the Pro models, perhaps 90Hz on the 17 and 17 Air is the way to do that.A19 chipJust like with its iPhone 16 line, Apple plans to ship two brand new chips for its iPhone 17 models.The base 17 and 17 Air will get the A19 chip, while the 17 Pro and Pro Max get an A19 Pro.How much difference will there be between chips? Probably not a lot for everyday tasks, as the A19 will still be a powerhouse for AI, gaming, and more. But the 17 Air chip will technically be a little underpowered compared to the A19 Pro.Single rear 48MP camera with bar designAs seen in the leaked image above, the iPhone 17 Air is expected to differ from its siblings substantially in the camera department.While the 17 Pro line again offers three rear cameras, and the base model two, the 17 Air will feature only one: the main 48MP Fusion camera.Rumors have been minimal around this cameras features, which could indicate it will be very similar to the existing main camera on the iPhone 16 line.Then again, its unknown what benefit the camera bar design will offer the 17 Air, so we could be in store for some surprises after all.24MP front cameraCurrently, the iPhones selfie camera is only 12MPand gets clearly inferior results to the rear cameras.Fortunately, Apple is bringing a welcome 24MP upgrade to the front camera on the iPhone 17 Air and all other iPhone 17 models.The new front camera is still unlikely to match the quality of the rear camera, but it should at least close the gap substantially.Apples in-house 5G modemFinally, theres a connectivity change coming to the iPhone 17 Air that no other 17 models will offer.Apples in-house 5G modem, which has been in the works for many years, is debuting this year and the 17 Air will get it.Well first see this new chip in the iPhone SE 4 this spring, but the iPhone 17 Air is set to receive it too.In some ways the new chip wont be able to match the current 5G modem from Qualcomm, but hopefully Apples tight integration of hardware and software will enable unique benefits that make up for that.iPhone 17 Air features: wrap-upThe iPhone 17 Air will no doubt be the most compelling fourth model in Apples lineup to date. Where the iPhone mini and Plus had their niche groups of loyal fans, the 17 Air stands to set the future tone for iPhone design. Its going to be a fun iPhone launch season this fall.Which iPhone 17 Air features are you most excited about? Do you plan to buy the new model? Let us know in the comments.Best iPhone accessoriesAdd 9to5Mac to your Google News feed. FTC: We use income earning auto affiliate links. More.Youre reading 9to5Mac experts who break news about Apple and its surrounding ecosystem, day after day. Be sure to check out our homepage for all the latest news, and follow 9to5Mac on Twitter, Facebook, and LinkedIn to stay in the loop. Dont know where to start? Check out our exclusive stories, reviews, how-tos, and subscribe to our YouTube channel