The hair spray can has no aim when it is flying around just as Oedipa has no goal when she is traveling around. The can is flying around bouncing off of whatever it hits and is out of control. Oedipa is traveling around San Narciso just going where ever people take her and really has no destination in mind. Both Oedipa and the can are traveling aimlessly around their respected areas.
The can is flying around the room because Oedipa knocked the can over and the top broke off. The can then started flying around the room, "The can hit the floor, something broke, and with a great outsurge of pressure the stuff commenced atomizing, propelling the can swiftly about the bathroom"(36). The can is fueled by something in side of it. The stuff inside the can sends it around the bathroom even though it does not know where it is going.
Oedipa starts traveling around San Narciso but she does not have a destination. She is being fueled by something inside her just as the can was. The stuff inside Oedipa that sends her around San Narciso is her curiosity. Her curiosity in the meaning of the Tristero and the meaning of W.A.S.T.E. are what sends her around San Narciso. She does not know where she is going but she will go until her fuel runs out just like the can.
Oedipa travels around the city of San Narciso without a real destination. She will get temporary destinations but no final destination. The can does not have any real destination either. The can will get a temporary destination just as Oedipa will. The can's temporary destination changes each time it hits its destination (e.g., a wall or other object). Oedipa's temporary destination changes when she reaches it (e.g., a store or other location) just like the can's does.