As such, multiple companies commenced work on their own conceptual designs for VTOL-capable interceptor aircraft; in order for these designs to be operationally relevant and viable, it was recognised that it would be necessary for the flight performance to equal that of conventional interceptors of the era, such as the modern Lockheed F-104G Starfighter. In conjunction, Germany's Federal Ministry of Defence (BMVg) championed for the merger of the competing companies; it deliberately withheld the issuing of a development contract in order to incentivise companies to undertake such activities.