In a mixing bowl, whisk flour, cornstarch, milk, oil, chili powder, and salt until smooth.
Place panko in a shallow dish.
Dip cauliflower florets in the batter, then press into panko until fully coated.
Arrange florets in a single layer in the air fryer basket.
Air fry at 400°F for 8 minutes.
While cooking, whisk together mayo, sriracha, and maple syrup for the sauce.
Transfer cooked florets to a bowl, toss with sauce until coated.
Return coated florets to air fryer and cook 4 more minutes at 400°F.
Serve hot with extra sauce if desired.