Joby Aviation has agreed to acquire Resonant Sciences, an Ohio-based maker of radio frequency and sensor systems, for $500 million in cash and stock, deepening the electric air taxi developer's push into the defence sector. The deal, disclosed in a regulatory filing on Tuesday, will see Resonant become a dedicated defence division within Joby, allowing the rest of the company to concentrate on certifying, manufacturing and launching its electric urban air taxis.

Resonant's co-founder and chief executive, J. Micah North, will lead the new division, which absorbs Joby's existing defence work, including turbine-electric and hydrogen-electric aircraft development and its autonomy technology stack. Resonant brings $100 million in trailing 12-month revenue and access to classified US government programmes, complementing Joby's earlier defence tie-up with L3Harris Technologies. The acquisition follows a pattern for Joby, which bought Blade Air Mobility's helicopter rideshare business for about $125 million last year to secure near-term revenue; Blade contributed $36.2 million of Joby's $38.6 million in second-quarter revenue.