It would be something if they could have the turbine burn...

It would be something if they could have the turbine burn hydrogen gas.

The drone would be covered in solar cells, whilst the inside would hold a battery, which together with a fuel cell could turn water into hydrogen.

Finally, the drone would have to be able to sense bodies of water in order to refuel....perhaps, then it would be able to continue gliding with propellers for a large part of the day using direct solar power, whilst using battery at night and building up the hydrogen fuel for the turbine, to use when required....