The iPad Air 2 has a 9.7-inch Retina display with a resolution of 2048x1536 at 264 ppi. It features LED backlighting with IPS technology, is fully laminated, and has an anti-reflective coating. However, it only supports the sRGB color standard.

The iPad Air (3rd generation) upgrades to a 10.5-inch Retina display with a resolution of 2224x1668 at 264 ppi. It also features LED backlighting with IPS technology, is fully laminated, and has an anti-reflective coating. Additionally, it supports the P3 wide color gamut and True Tone, which adjusts the display’s color balance based on ambient lighting.

The iPad Air (4th generation) has a larger 10.9-inch Liquid Retina display with a resolution of 2360x1640 at 264 ppi. This display also includes LED backlighting with IPS technology, an anti-reflective coating, and supports P3 wide color and True Tone, offering the best color accuracy and viewing experience among the three.

The iPad Air 2 is powered by the A8X chip, which was advanced for its time but is now considered outdated, suitable mainly for basic tasks.

The iPad Air (3rd generation) features the A12 Bionic chip, which includes a 6-core CPU, 4-core GPU, and an 8-core Neural Engine, providing significantly better performance, efficiency, and the ability to handle more demanding applications compared to the A8X chip.

The iPad Air (4th generation) is equipped with the A14 Bionic chip, which is even more powerful. It features a 6-core CPU, 4-core GPU, and a 16-core Neural Engine, making it capable of handling intensive tasks such as video editing, gaming, and advanced machine learning tasks with ease.

The iPad Air 2 and iPad Air (3rd generation) both have an 8MP Wide rear camera with an f/2.4 aperture, capable of recording 1080p HD video. The front camera on the iPad Air 2 is a 1.2MP FaceTime HD camera, while the iPad Air (3rd generation) improves on this with a 7MP FaceTime HD camera.

The iPad Air (4th generation) offers a 12MP Wide rear camera with an f/1.8 aperture, capable of 4K video recording, and a 7MP FaceTime HD front camera. This makes the iPad Air (4th generation) the best choice for photography and video recording.

The iPad Air 2 and iPad Air (3rd generation) both use the Lightning connector for charging and data transfer. They support Wi-Fi 802.11ac and 4G LTE cellular connectivity.

The iPad Air (4th generation) introduces a USB-C connector, which allows for faster data transfer and more versatile connectivity options. It also supports Wi-Fi 6, offering faster and more reliable wireless performance, while still maintaining 4G LTE cellular capabilities.

The iPad Air 2 does not support any Apple Pencil, limiting its use for creative tasks.

The iPad Air (3rd generation) supports the 1st generation Apple Pencil, making it more suitable for note-taking, drawing, and other creative applications.

The iPad Air (4th generation) supports the 2nd generation Apple Pencil, which offers wireless pairing and charging, and attaches magnetically to the iPad. It also supports the Magic Keyboard, providing a more complete and advanced experience for users who want to use their iPad as a laptop replacement.