Hey there Lees52,
It sounds like you've been having some issues transferring your data from your previous iPad to your newer one due to the difference in software versions.
Are these the steps that you're using to start the transfer?
If so, then your iPad needs to be able to run iPadOS 13.4 to use Quick Start. You can use this guide to see the highest version of iPadOS your iPad Air is capable of using: Apple security updates
If your iPad is not compatible with iPadOS 13, then you do have other options to transfer your data. You can choose to restore your data from a backup made from your previous iPad. Just follow the steps listed here: Restore your iPhone, iPad, or iPod touch from a backup
Cheers!