What are these things hanging off the trailing edge of the wing?
I've seen them in almost all of the aircraft I've flown in, and can't remember if they're exclusively Boeing or Airbus.
Those are static wicks -- Basically these are little wires screwed to the airframe.
Their purpose is to discharge the static electricity that an aircraft picks up moving through the air - especially in clouds.
The static discharge tends to happen at "pointy" protrusions from the aircraft - if this happened through antennas it could cause radio and navigation interference, so to prevent that static wicks are installed, providing a low-resistance protrusion for the charge to dissipate through (and as an additional benefit, dissipating the charge helps ensure your aircraft doesn't attract lightning strikes).
These are static wicks or static dischargers. They dissipate static electrical buildup caused by the friction of air flowing over the surface of the aircraft. The air friction tends to separate electrons from their atoms just as rubbing a balloon tends to do, causing an imbalance of electrical charge on a body. The wicks work by providing a pointed surface where airflow separates from contact with the aircraft body. The excess charge tends to flow into the air and is swept away from the aircraft.
It's called static dischargers since aircraft body or fuselage is made up of metal and carrying tonnes of fuel and electronic devices, we will have to remove the static electricity charge from the fuselage to the air in order to not ignite the fuel or disturb the electronic devices, and that's how it's done ! :)