Virtual reality (VR) technology can revolutionize military aircrew and pilot training by accurately simulating task performance in a high-fidelity and multisensory virtual environment at significantly lower cost than traditional simulators. User interaction must be intuitive and natural, however, so aviators can train as they fight, while avoiding frustration. Groups within the Air Force are developing VR solutions to fit within their training curricula but are encountering challenges implementing natural interaction with virtual aircraft controls.In the proposed Phase I, collaboration with leaders in Air Force VR aircraft training development will be leveraged to determine standardized human-machine interface (HMI) capability requirements, integration approach(es), and interface design(s) that can be utilized by the Air Force at large. The objective is to create an API capable of integrating HMI technology independently of training development tool set across Air Force programs. A standardized API will enable rapid integration of emerging HMI technology and address the problem of costly duplication of effort across groups within the Air Force, allowing the success of one Air Force project to be rapidly adopted and integrated into others. Implementation of the Air Force-wide API would occur in a notional Phase II.virtual reality,mixed reality,hand tracking,Human-Machine Interface,API design,Aircrew Training