Its ironic how these $200-$300 cases are meant to protect the phantom.
Many million posts ago, a member on the forum blamed poor baggage handling when he checked in his Phantom in a ABS case (I cant recall the brand). His Gimbal was actually crushed from the compression.
My theory is that when the plane takes off, the ABS case expands like a balloon. With that amount of pressure, some air slowly escapes and the ABS case then equalises after a few hours and the case goes back to its normal shape. Then when descending at a fast rate, the ABS case is then crushed by the outward pressure.
Its best practice to carry on the phantom and batteries. Leave your screws and tools to be checked in.