Peel and slice the beets into ~1/16th inch (2 mm) thick rounds. (If you have a mandolin, I recommend using that. Otherwise, you can very carefully use a sharp knife OR you can try using a vegetable peeler to cut it into thin strips.)
Add the beets to a bowl along with the oil and salt. Toss to coat and then rest for 5 minutes to give the beets a chance to sweat out some of their moisture.
Place beet chips in 1-2 layers (slightly over lapping- you may need to work in batches) and air fry at 325 °F for 15-20 minutes.After every 5 minutes, toss or stir to ensure they cook evenly. Keep a close eye after 15 minutes of cooking so that they don't burn.
After cooking, remove to a dish to cool for 5-10 minutes. They will continue to crisp up as they cool.
Enjoy!
Notes
LeftoversPlace cooled air fryer beet chips in an airtight container or zip-top bag for up to 1 week at room temperature.