In a large bowl combine yogurt, garlic, lemon, salt, cumin, onion powder, paprika, turmeric, black pepper, cinnamon & red pepper flakes. Add chicken & coat completely. Marinate for a minimum of 30 minutes but up to overnight (do not recommend going beyond 36 hours as the yogurt will begin to break down the chicken).
Air fry chicken thighs in an even layer 400°F for 20 to 24 minutes, flipping halfway in a single layer, in batches as needed.
Head a skillet or grill/grill pan over medium-high heat and spray with oil. Cook the chicken about 15 to 20 minutes, turning halfway.
When done, transfer to a cutting board and slice. Build pita sandwiches or serve over salad with sliced chicken, ½ cup shredded lettuce, onion, 1 slice tomato and tzatziki, if desired.
