Dot Matrix has had two hover cars she has owned in the past.
The first was a pink car that Dot owned when she was a teenager at the time she built Dot's Diner. This small car had two seats and a small back compartment. It was similar to a jeep in design. When Mainframe's Twin City was destroyed, Dot and Enzo used the car to drive to the remains of the city to search for their father, Welman Matrix. Soon after landing in the hollow ruins Dot and Enzo meet Guardian Bob for the first time, when he arrived in Mainframe to help with the disaster. (What's Love Got To Do With It?)
Dot's second car was a small white car with gold highlights. She purchased this car soon after Bob had arrived in Mainframe. Bob was trying to enter a Game Cube, but Megabyte ordered a squad of ABC's to stop Bob from entering the Game so that the virus could blackmail the guardian. The ABC's knocked Bob off his Zip Board and he fell toward the street below. Dot and Enzo flew in just in time in her car and caught Bob in its back seat. They landed near by and Bob began to scan the Cube with Glitch. They all watched helplessly as the Game was lost and the sector and everyone inside was nullified. (The Tearing)
Neither of Dot's cars have been seen for a long time. She most likely sold them for some reason and now sticks to using zip boards. On occasion Dot will use Bob's Car to get around Mainframe.