Obligatory plug for Dragonfly: https://www.nasa.gov/dragonfly/dragonfly-overview/index.html https://www.nasa.gov/dragonfly/dragonfly-overview/index.html You _c

Obligatory plug for Dragonfly: https://www.nasa.gov/dragonfly/dragonfly-overview/index.html https://www.nasa.gov/dragonfly/dragonfly-overview/index.html You _can_ use nuclear power similar to the rover if the lift / weight isn't prohibitive. That means a bigger copter in a thicker atmosphere and lower gravity. Since the power is generated by temperature gradients, cold helps too. Perfect for Titan.