F-35 Lightning II to receive internal weapons bay upgrade

The F-35 Lightning II is slated for a significant internal weapons bay upgrade known as ‘Six in the Bay’ (SITB). This modernization effort, part of the broader Block 4 upgrade roadmap, aims to increase the stealth fighter's internal missile capacity from four to six missiles by September 2030.

This 50% increase in internal capacity allows the aircraft to maintain its low-observability stealth profile by avoiding the use of external weapon pylons, which would increase its radar signature. The upgrade is intended to improve survivability and mission endurance in high-intensity combat environments by providing a larger weapons reserve before the aircraft must return for rearmament.