Preheat the air fryer: Set it to 375°F (190°C).
Lightly coat the basket with cooking spray or brush with oil to prevent sticking.
Mix the burger base: In a large bowl, combine ground turkey, feta, red onion, parsley, dill, oregano, garlic, lemon zest, lemon juice, olive oil, cumin (if using), salt, and pepper. Stir just until combined. Do not overmix or the burgers can turn dense.
Shape the patties: Form 4 equal patties about 1/2 to 3/4 inch thick. Press a slight indent in the center of each to help them cook evenly and stay flat.
Air fry: Place patties in a single layer in the preheated basket.
Cook for 12–14 minutes, flipping once halfway through, until the internal temperature reaches 165°F (74°C).
Rest briefly: Let the burgers rest for 3 minutes to lock in juices.
Assemble and serve: Add to buns or pitas with tzatziki, tomatoes, cucumbers, red onion, and greens. Finish with a squeeze of lemon for brightness.