Uber announced that it plans to collaborate with the U.S. Army in order to develop a quiet VTOL (Vertical Take Off and Landing) aircraft rotor technology, one that could see flying cars jumping from science fiction to reality.

The ride-hailing giant, together with the Army’s Research, Development and Engineering command stated that around $1 million will be spent to develop and test the prototypes for the rotor system that’s designed specifically for vertical takeoffs and landings.

According to Autonews, the system would feature two rotors on top of each other, rotating in the same direction – in turn resulting in quieter operation than what you’d otherwise get with conventional stacked rotor systems.

“Achieving ultra-low noise is one of the critical obstacles [to deploying aerial taxis in urban areas]”, said Uber Elevate engineering boss, Rob McDonald. Uber is also looking into establishing more alliances with government agencies in an effort to have an airborne taxi prototype up and running by the year 2020.

Meanwhile, the Army is interested in developing a new generation of unmanned drones that can take off vertically and are quieter than current models.

Aside from Uber, companies such as Boeing, Airbus and a venture backed by Alphabet Inc co-founder Larry Page are also investing in trying to build small, automated and electrified aircraft to be used in congested cities.