This article provides a concrete example for using and creating a virtual environment for computer-aided design of complex systems. The subject area is design, and the object of research is an aircraft. CAD creates a parameterized 3D model, which is demonstrated and processed on a virtual stage using special equipment. Special equipment such as the HTC Vive Pro virtual reality helmet and the included controllers. The virtual assistant of the designer allows you to create detailed parameterized models of an aircraft, in particular, a transport aircraft based on the An-124 Ruslan, and virtual reality helps the user to learn more about the created project and make the necessary optimization edits directly in VR space. By changing the model in VR space, it will change in the main project. The work is a continuation of the development of a decision-making system, a virtual assistant to the designer: "Robot designer", whose application interface has been defined. The main control menu for the user in virtual space is shown, and the aircraft with the fuselage skin and cockpit removed is also shown. Plans for further use of virtual reality technology in the design of complex systems and training of specialists with the profile of aircraft engineers are presented.