The ornamental design for a flyfan, as shown and described.
FIG. 1 is a perspective view of a fly fan, showing my new design;
FIG. 2 is a perspective view in the open configuration thereof;
FIG. 3 is another perspective view thereof;
FIG. 4 is a front view thereof;
FIG. 5 is a rear view thereof;
FIG. 6 is a left side view thereof;
FIG. 7 is a right side view thereof;
FIG. 8 is a top plan view thereof; and,
FIG. 9 is a bottom plan view thereof.
The broken line showing of portions of the fly fan is included for the purpose of illustrating environment only and forms no part of the claimed design.