Great achievement, NuttX belongs to the increasing list of embedded OSes, with FOSS licenses based on MIT and Apache, moving away from GPL.

Besides NuttX, we have Zephyr, FreeRTOS, Arm Mbed, Azure RTOS (Eclipse ThreadX), ESP-IDF,...

We have used NuttX for operating both fixed wing and multi-rotor based small UAVs back in 2019 for plantation monitoring.

Looking forward to use it for Gyrocopter UAV where it's like a Goldilocks of UAV, longer range than multi-rotor UAV and more maneuverable than fixed wing UAV.