How did this craft get from Newark the Sky Harbor? Wait…reverse that how did it get back from Sky Harbor?
Looks like you are tracking a particular flight, not a particular airplane.
It would have helped to put the flight number in your posting.
Based on the flights I’m guessing it’s a United flight in the 1800 series. These are charter, maintenance, and ferry flights.
Easy enough to find in the flight finder with the route and time: flightaware.com/live/flight/UAL1182
The plane gets to it’s origin as other flight numbers.