Is there an adapter to the USB-C charger to the old charger?
I hate that my new iPad Air only uses USB-C charger. Is there an adapter I can use so I can charge the iPad Air in a regular iPhone charger?
Question marked as
Yes.
But really you should be using the 18/20W power/charging adapter block that has come with your new iPad Air 4.
The iPhone power/charge block will not be a powerful and your iPad Air will tale longer to charge, as a result.
Use the 18/20W power/charging block that came with your new 2020 iPad Air 4.
It was included in the box for a reason.
Best of Luck to You!