The piloting skill says that it unlocks other skills for flying, but the only thing right now is drop-ships, which only take Piloting 1. Is there any reason at all to train above 1 in piloting?
There is not a reason currently, due to the only thing available being drop-ships.
As CCP does updates for the game during the open beta (and continuing after release) there may be skills or ships that require or benefit from a higher piloting skill.
As of patch 1.7 this skill is no longer in the game. This is now handled under the skill Vehicle Command.
The Vehicle Command skill provides no bonus of its own but it is required to unlock subsequent vehicle skills. They are (and require):
Both LAV (Light Attack Vehicle) and HAV (Light Attack Vehicle) skills only unlock the ability to operate those vehicles.
The Dropship Operation skill unlocks the ability to operate standard dropships. Raising this to Level 3 unlocks the Assault Dropships skill.
The Assault Dropships skill unlocks Assault Dropships of all races. It also increased small turret damage by 2% per level trained. Once this is trained to Level 1 you unlock the following skills:
Each level grants a 10% bonus to missile turret rate of fire and 5% bonus to the amount of maximum ammo for missile turrets to Caldari Assault Dropships.
Each level grants a 10% bonus to hybrid turret rate of fire and 5% bonus to the amount of maximum ammo for hybrid turrets to Gallente Assault Dropships.