The maiden voyage of the time machine took Onassis from the 19th century to Danville circa the late 2020s, arriving moments after Phineas, Ferb and Isabella depart to return to their own present. After pronouncing the test run a success, Onassis decided to stay in this time period when he learned corn dogs had been invented. It is not stated how he would have conceived of this kind of food, given that he apparently had not seen them previously. 35 year old Candace uses this version of the time machine to return to the day the rollercoaster was built, as this was a day she was confident she would be able to bust her brothers.
The time machine appears to only be able to travel through time, remaining in the same geographical position throughout its journey. It can hold two adults or three children. ("Phineas and Ferb's Quantum Boogaloo")
Another version of the time machine was built by Isabella and the Fireside Girls from plans drawn up by Phineas and Ferb. It was used to rescue Phineas, Ferb and Candace from the Mesozoic Era after their original time machine was destroyed by a T. rex. It can hold up to 12 small passengers and also appears to only have time positioning and not geographical positioning. ("It's About Time!")