Pima County sheriff's Deputy Tracy Suitt says the wreckage was found Sunday south of Tucson during a search by the sheriff's department and Tucson police that included air units. No one else was aboard the unregistered aircraft.
The Federal Aviation Administration says it doesn't certify ultralight aircraft or investigate accidents involving them.
The sheriff's department received a call from a witness around 9:30 p.m. Saturday saying he saw the plane go down "a couple of days ago" near Sahuarita and Wilmot roads. Suitt says the man didn't report the incident sooner because of his immigration status. That status wasn't known.
On Saturday, darkness suspended a search, which resumed Sunday.