Depending on the type of drone and its specific application, here are some non-functional requirements to consider:
1. The drone's flight path should allow it to avoid any obstacles or obstructions upon which it may crash.
2. Recovery time after system failure should not exceed 0.5 seconds.
3. Within a day, total system downtime should not exceed 5 seconds.
4. The drone should be able to return to the launch site if it meets any unfavourable conditions while flying.
5. On reliability, this system relies on the durability of the physical user interface, the network connection in the area the drone is being operated in.
6. The drone will fly below 400 feet above the ground to prevent collisions with FAA regulated aircrafts in public airspace.
Please provide specific information about the drone in question.