All-new iPad Air with advanced A14 Bionic chip available to order starting today
apple.com
apple.com
I wonder if they are holding it up because it will use the same CPU as whatever is in the ARM Macbooks.
Also with APPLESi Macs, they're natively running iPad apps, so there is some kind of chance they meld the Pro line and the MacBook line into a single device capable of running both platform's Apps, though I don't actually expect that gen1 of the new platform.
iOS is a console ecosystem, so any new one is guaranteed to last 5 years or more with excellent performance.