One of the reasons why Apple is able to call this particular model the "iPad Air" is that it's notably thinner and lighter than the entry-level model iPad. Either model measures in at 250.6x174.1mm, but the iPad Air is only 6.1mm deep, compared to the 7.5mm on the regular model iPad. The iPad Air is also lighter, at just 456–464 grams (Wi-Fi or LTE) compared to 483–493 grams for the regular iPad.
That's not a difference that you're going to notice unless you do happen to be weighing them up side by side. But it does contribute to one of the iPad Air's selling arguments, because it gives it a small touch of luxury and Apple very much likes to position itself as a luxury brand.
Much of that width difference comes down to the fact that the regular Apple iPad has a discernible air gap between the front glass and the actual display, where the iPad Air's glass sits neatly against the glass. This lowers reflectivity, but it's not the only trick that the Apple iPad Air brings into play. Apple markets them both as "Retina" displays, but as always that's a quite meaningless marketing term.
2,160x1,620 pixels is enough to be "Retina" for the regular iPad and the iPad Air bumps that up slightly to 2,224x1,668, which is presumably "Retina plus a few pixels you wouldn't spot unless you squint really hard". Naturally, that doesn't look quite so good in the marketing copy.
Where the Apple iPad Air's display does make more of an impact is the fact that it also supports Apple's True Tone technology. This measures the ambient light and adjusts the display on the fly to render a more accurate white under any given circumstance. No, the iPad Air isn't deeply racist – in this case it's a question of accurate colour display because if you can crack getting white to display properly without any kind of tint then you can render any other colour more accurately even if you're in a darkened or overly bright environment. True tone really does make a significant difference to just about every display task on the iPad Air, whether you're simply scrolling web pages or watching video.

The controls on the iPad Air follow the classic iPad scheme, with a TouchID sensor at the base, volume controls at the top right and power button nestled just above. The left-hand side houses the connector that makes the iPad Air compatible with Apple's smart keyboard, a feature that works across all of the full-size iPad models. Sorry, iPad Mini owners, no shrunk-down Apple keyboard for you.
It's also one of an increasingly limited number of Apple devices that still has a regular 3.5mm headphone jack. Naturally, Apple would prefer that you hooked up with a pair of AirPods Pro or perhaps the Beats Solo Pro than a pair of cabled headphones, but at least the option still exists.
While Apple has become somewhat fancy with phones such as the Apple iPhone 11, the Apple iPad Air 2019 retains Apple's colour choice from years past, which means you've got silver, grey or gold – sorry, "Silver", "Space Grey" or "Gold" – finishes to choose from. Silver and Gold iPad Air models feature a white bezel around the display, while the Space Grey model uses a black bezel. I tested with a Space Grey model and I did find the black bezel less distracting than the higher-contrast white.