Soft cases are great at preventing dings and scrapes if you are the one moving your prize positions. However, if you are entrusting these prize positions to airport baggage handlers that don't give a damn about what might be inside choose a hard case. Which one you choose is up to your conscious and pocketbook.
When I was competing in years past, although not flying, I transported my Winchester 52B and Springfield M1A in a Pelican hard case. I knew the guns were protected and didn't worry about anything throwing there sight-in settings off.
A soft case is good for general trips to the range if you are the only one handling but hard cases are better when other people are handling. Weight is irrelevant when protection is the ultimate goal.
What is your willingness to accept damage caused by poor handling of others?