Since hardshell cases are not hand tailored for your individual instruments, you have to secure them with bubbles or paper to avoid bumping inthe case.
Following the German Army's Regulations for boxes and crates I learned that you can fix holders in the inside which hinder the heavy goods (esp. shells and grenades) from moving during transport. Similar precautions can be made in rectangular boxes for instruments. If you can't do it by yourself, join your local joiner.
Another method is filling the the box or case with special foam and only a spare room the instrument fits exactly into, like the cases for recorders (at least in Germany this is standard). Friend of mine did it, but alas, he stopped his business and moved.
Yeah, Heathrow ... Another friend of mine got the mechanics of his brass bass demolished, fortunately on the way back after our performance. Bought a hardshell case immediately after the repair. Transport in the hold did the instrument no harm by temperature; Whe transporting string or reed instruments, consider a good insulation in the case. Shouldn't be a grand technical problem.

Wilfried