Uber Technologies(NYSE:UBER) CEODara Khosrowshahiexpressed doubts aboutElon Musk's vision forTesla Inc.'s(NASDAQ:TSLA) future robotaxi fleet.

Khosrowshahi's Concerns:Musk expects his company's robotaxi fleet to function like a combination of Airbnb and Uber. While a certain portion of the fleet will be owned by Tesla, individual customers can also add or subtract their vehicles to the robotaxi fleet at will. As for riders, they can summon a car using the Tesla App, Musk said during the company's second-quarter earnings call last month.

Khosrowshahi, however, is not sure if a...