Cut the carrots into½-inch thick fries, about 3 inches long. Toss with the olive oil, using your hands or tongs to make sure they’re well coated. Sprinkle with the ranch seasoning and toss well to coat.
Preheat the air fryer to 375°F. Add the carrots and arrange in a single layer (cooking in batches if necessary). Cook for 18 to 20 minutes, or until tender and crispy around the edges, shaking the tray halfway through.
While carrots are still hot, sprinkle with fine sea salt, if desired.