The ornamental design for an airflow drying apparatus, as shown and described.
FIG. 1 is a perspective view of a air flow drying apparatus showing my new design;
FIG. 2 is a Front side elevation view thereof;
FIG. 3 is a Right side elevation view thereof;
FIG. 4 is a Top plan view thereof; and,
FIG. 5 is a Bottom plan view thereof.
The broken lines shown in the drawings are included for the purpose of illustrating unclaimed portions of the air flow drying apparatus, and form no part of the claimed design.