Air fryer

The design is the features of shape, configuration and ornament of the portions of the air fryer as shown in solid lines in the drawings. The portions shown in stippled lines do not form part of the design. Drawings of the design are included. FIG. 1 is a perspective view of an air fryer showing the design; FIG. 2 is a front view thereof; FIG. 3 is a rear view thereof; FIG. 4 is a right-side view thereof; FIG. 5 is a left-side view thereof; FIG. 6 is a top view thereof; and FIG. 7 is a perspective view showing the air fryer in an open position.