Make the candied bacon. Lay bacon in a single layer in the air fryer basket. Sprinkle each slice with brown sugar and a little black pepper, pressing to adhere. Air fry at 350°F for 8–10 minutes, until crisp and caramelized. Transfer to a rack to cool and firm up.
Fry the eggs. Preheat the air fryer to 375°F. Grease a small oven-safe pan or ramekin and place in the basket. Crack in an egg, season with salt and pepper, and air fry at 375°F for 5–7 minutes, until the white is set and the yolk reaches your desired doneness.
Toast the croissants. Slice croissants in half. Place cut-side up in the air fryer at 350°F for 2–3 minutes, if desired.
Assemble. Place a slice of cheese on each bottom croissant half, add a fried egg, then top with candied bacon. Add the top half of the croissant.
Melt and serve. For an extra-melty sandwich, return assembled croissants to the air fryer at 300°F for 2–3 minutes. Plate, serve, and enjoy immediately.