There are some things about the iPad Air 3 which we can be fairly confident about. For one thing it's likely to run iOS 10, though iOS 9 is always possible if it arrives sooner rather than later.
iOS 9 brings improvements to Siri and Apple Maps, true multitasking for iPads, a new keyboard and more. So look forward to all that on the iPad Air 3 at a minimum. If it has iOS 10 that's sure to bring even more new features, but what form they'll take remains to be seen.
Another change we might see is a larger screen. Apple's all about making sure that users get the best out of the tablets they buy, and with the ability to run multiple apps on a screen, more space to do so would be welcomed
Whether that would be a slight increase on the 9.7-inch Retina display we see today, or something that boosts it up to 12 inches (and thus taking the iPad Air 3 into iPad Pro territory) is unclear as we've yet to see much in the way of a leaked framework for the new tablet.
However, Apple is likely to try and keep the same footprint while improving the screen ratio a touch - now most apps can scale to any screen, (which is why the iPad Mini 4 has the same pixel count as the larger device) this would likely not present much of a problem.
The iPad Air 3 is also sure to get a newer, faster processor. The iPad Air 2 has an A8X chip, but we're already up to the A9X on the iPad Pro, so we'd expect that at a minimum and quite possibly an A10 chip.
There's a good chance we'll get more RAM too. The iPad Air 2 has 2GB of RAM, but Apple has since launched the iPad Pro with 4GB. As the name suggests though the Pro is aimed at more serious productivity, so the Air 3 might not have that much, but 3GB wouldn't seem unreasonable.
The design probably won't be much different, so expect a slim aluminium shell. If anything it might get even slimmer and lighter, as that's the direction Apple has been going with its Air range, but with the iPad Air 2 already just 6.1mm thick and 437g we're not at all convinced that a further reduction would be beneficial.