Same for thunderbolt.Also will it never miss hitting a Pokemon in the air.
Thunder can hit Pokemon using Fly and Bounce, the latter dealing double damage.
http://pokemondb.net/move/thunder
Yes thunder can hit Pokemon using fly and hit bounce too. Only bounce gets double damage if that's the boost your taking about. Nothing is special about thunderbolt though...
Thunder's attack won't increase if the opponent is in the air, same thing for Thunderbolt. It can still miss if the opponent is in mid-air, though. The only way it will never miss is if you have Rain.
Thunderbolt will not work. It does not hit with flight.
And unless you have an Electric Gem, Life Orb, Choice Specs, or another Power-Boosting item, Thunder is a usual Thunder.