The announcement offers the first detailed look at the supply chain behind an aircraft that BAE Systems developed largely in secret at its Warton site in Lancashire. GKN Aerospace said the structures were delivered flight-ready, having progressed from a clean-sheet design within what it described as an accelerated timeline. BAE Systems has positioned Brontanax as a pre-series, pre-production prototype, with its FalconWorks rapid development unit leading the design. The prototype flies with a Williams International engine, although BAE Systems expects to transition to a powerplant from Rolls-Royce’s Orpheus family. Brontanax is BAE Systems’ answer to the Royal Air Force’s Storm Fighter requirement, under which the latest Defence Investment Plan allocates £300 million ($400 million) to loyal wingman development.