Got this email from Ready Made RC the other day. A lot of people are confused by this law because it says "passenger aircraft". RMRC sells their own branded batteries and are concerned with shipping them though. My understanding of a "passenger aircraft" is an aircraft designed to transport passengers (think airline), vs. one designed to carry cargo specifically.
Here is more on the changes that will go into affect:
http://www.iata.org/whatwedo/cargo/dgr/Documents/lithium-battery-update.pdf
Several changes are going into effect on April 1st, 2016 regarding how Lithium Polymer batteries may be shipped via air. First, all international shipments of lithium batteries not in or with equipment (batteries by themselves) are prohibited as cargo on passenger aircraft. This means there are now over 100 countries to where we will not be able to ship batteries. Second, a 30% state of charge limit will be placed on batteries that will be traveling via air. We believe this is not only unsafe as the battery is not stable at 30% charge, but long periods at this charge dramatically increases the chance that a cell will go bad.
Here is more on the changes that will go into affect:
http://www.iata.org/whatwedo/cargo/dgr/Documents/lithium-battery-update.pdf