Here is the real scoop:
In compliance with Federal Law on interstate commerce pilots will be taxed based on the state they live if they work less than 50% in any given state. Therefore any pilot who is a resident in the state of Ky is subject to both Ky state taxes and any local taxes in the county they work.
Jefferson Co allows for two rates depending on if you are a Jefferson Co resident (2.2%) or not (1/45%). In addition Jefferson Co does not tax wages not earned in Ky/Jeff Co. Pilots can estimate the time they work in Jefferson Co and calculate the % to total credit hours which will be applied to the total Gross wages.
For example if you work 10% in Jefferson Co and your wages are $5,000, then $500 is subject to the tax at either the 2.2% ($11) or 1.45% ($7.25).
In addition if you work less than 5% of your time in Jeff Co there is no withholding.
Lastly the pass-through % is only an estimate. You can adjust at any time and at the end of the year you can recalculate the prior year and file for a refund if you calculate that you over paid.

By the way Indiana has local taxes as well, the difference is since the employee does live in Ky the company can not withhold, but the employee may be still liable for paying the tax.
Other states that have local employment taxes are: MI, PA, OH, Al, IN, IL & WV.