Preheat the air fryer to 400°F
Place 1/4 cup popcorn kernels in a small, air-fryer-safe baking dish or foil tray
Add 1 teaspoon oil and toss to coat
Cover the dish tightly with foil
Poke a few small holes in the foil
Put the dish in the air fryer basket
Cook for 8 to 12 minutes
Shake the basket halfway through
Stop cooking when popping slows to 2 to 3 seconds between pops
Carefully remove the dish
Season the popcorn as desired
Serve immediately