Why would there be air in your well water lines?

-Air in pipes is due to faulty connections or pump entry being at water level ( instead of deeper) and sucking air.

There is no air in groundwater. If there is air in your well water lines then either your pump or foot valve is at static water level and sometimes sucks air, - or there is a small leak in the pipe which will both admit air and leak water, depending on pressure. If you are using a Jet-pump at a well shed, air leaks are quite common. Most people do not know how to properly attach water pipes to fittings. It is also possible that the down pipe into the well has vertical cracks. This too is common certain kinds of pipe.