iPad Air 4
How to force close apps (swiping) like I did on the Air 2 (which was double click the Home Button and then swipe)
iPad Air, iPadOS 14
From the bottom edge of the screen, swipe upwards to the centre of the screen - and pause, briefly, before lifting your finger from the screen; this will open the Task Switcher.
You can now manipulate tasks as before.
This method works equally well on iPad models that incorporate a Home Button.