Need help designing an airplane legal battery pack
Its similar with the DeWalt tool batteries, they are 54V which is higher than allowed for shipping. Their solution is to physically disconnect the cells with a "transport cap", so they are actually 3x18V. When the battery is attached to the tool, the cells are ganged up in series to produce 54V.

https://www.2helpu.com/uploads/2016%20-%20XR%20FLEXVOLT%20Battery%20Shipping%20Website%20Copy%20ANZ.pdf