Originally Posted by Mr.Nuke

No I'm fairly confident your initial typo hypothesis was correct. As rolltribe said this flight number is constant with charters or positioning flights. FlightAware has the filed flight plan and track log. The flight plan is a DEN-EWR flight plan. So they were re-positioning the plane. For whatever reason mid-flight they deemed the plane was needed in IAD more than EWR. Over Illinois the plane diverted to IAD to operate the OP's flight to PHX, but it was initially misfiled AID, the same three letters as IAD.

There is nothing in the track log to support this.

Originally Posted by StuckinITH

If it was a charter it would have landed there and they would not have corrected the diversion in one minute. An operator mistyped the diversion: wrote AID instead of IAD.

The original flight was supposed to be EWR as the original gate of arrival was consistent with the numbering in Terminal C of EWR.