1Pour boiling water on gelatin in medium bowl; stir until gelatin is dissolved. Stir in cold water and pineapple. Refrigerate about 45 minutes or until thickened but not set.
2Lightly brush six 1/2-cup salad molds with vegetable oil. Stir carrot into thickened gelatin; pour into molds. Refrigerate about 4 hours or until firm.
3To unmold salads, dip molds into hot water for 10 seconds. Place salad plate upside down onto each mold; turn plate and mold over, then remove mold. Top salads with mayonnaise.