The PHASA-35 high-altitude, long endurance unmanned aerial vehicle (HALE UAV) could stay airborne for a whole year using nothing but solar power. The project is a collaboration between BAE Systems and Prismatic. Test flights will take place next year and finished aircraft could be shipped to customers in 2020 or 2021.
Airbus is building two Zephyr models for different sized payloads. The smaller, Zephyr S is already in production, while the slightly larger Zephyr T is still in development. Zephyr S has set an endurance record of 14 days of uninterrupted flight.
Collected and summarized from the source below by Giang Tan https://i-hls.com/archives/84604