Toutou
Autonomous sailplane: - flies in 3D space with pitch, roll, yaw - has both MAX (Vne) and MIN (stall) speed, can't stop and wait - can't even stop descending (!) - HEAVILY influenced by wind and thermal conditions - pretty unstable, oscillates when upset - can not use ground as visual reference reliably - flying one is no joke even for a human, requires serious training
Good luck with your full autopilot.
Ruby is a perfectly good scripting language. I use it with love and passion to do the kind of stuff other people use Python, Perl or Bash for.
Where did you get that from? Some of them, sometimes, with exceptions, with mixed success. Certainly not Prague (which is where I live). The public transport system is absolutely fantastic, but as of now it's at 100 % capacity (locally) and the city center is still full of cars. People need to move stuff, plumbers, electricians can't haul their tools around in a bag, the streets need to remain perfectly accessible for ambulances and firetrucks.
Don't forget that most European cities are hundreds of years old, built on river banks, rocks, hills, the complete opposite of most US cities.