Peel the mangoes and slice the flesh away from the pit. Cut the mango into thin, uniform slices about 1/8 inch thick. Keeping the slices even in thickness is important so they all dehydrate at the same rate.
Lay the mango slices on a clean kitchen towel or paper towels and gently pat them dry to remove excess surface moisture. Drizzle the lime juice over the slices and toss gently to coat. If using, lightly dust with chili powder and a pinch of salt for a sweet-and-spicy variation.
Arrange the mango slices in a single layer in the air fryer basket or on the dehydrating trays, making sure the pieces do not overlap. You will likely need to work in batches.
Set the air fryer to the dehydrate setting at 135 degrees F. Dehydrate for 6 to 8 hours, checking every 2 hours and flipping the slices for even drying. The mango is done when it is pliable and leathery but no longer sticky or wet to the touch.
Remove the dried mango from the air fryer and let it cool completely at room temperature. The slices will firm up slightly as they cool.
Store the dehydrated mango in an airtight container or resealable bag at room temperature for up to 2 weeks, or in the refrigerator for up to a month for longer shelf life.