She left with a friend before midnight, telling others she had an early flight home to catch for Christmas.
The Lebanese driver picked her up from Gemmayzeh and then drove to the nearby Achrafiyeh neighborhood where she lived, but did not drop her off there.
Police traced the suspect's licence plate through surveillance cameras on the highway, where he dumped the body around 4am, Lebanese news agency NNA reported.
The suspect has a criminal record, but it is not known if he was picking Miss Dykes up in his capacity as an Uber passenger or not.