The ornamental design for a traveltray for children, as shown and described.
FIG. 1 is a front perspective view of the travel tray for children.
FIG. 2 is a rear perspective view thereof.
FIG. 3 is a top view thereof.
FIG. 4 is a bottom view thereof.
FIG. 5 is a front view thereof.
FIG. 6 is a back view thereof.
FIG. 7 is a right side view thereof; and,
FIG. 8 is a left side view thereof.
The short, dashed lines in the drawings are used to denote stitching and form part of the claimed design. The longer, broken lines in the drawings showing printed design elements and male/female buckle components form no part of the claimed design.