However, these boxes proved not to be durable, as unlike their counterparts used on ships, they had to be unloaded at every nightly stop. At some point, an entrepreneur tackled this issue by creating a leather case with rigid sides and additional locks. This turned out to be lighter and far more durable than wooden boxes, due to its flexibility. These lid-covered cases remained popular until the advent of airlines, which required lighter luggage. This, combined with the Industrial Revolution, led to a surge in leather goods to meet new demands—business bags and folders, writing cases, leather wallets, leather bags, and more.