It was a fukked up situation, but not nearly the same. The people on the plane had to piss in bottles or they pissed on themselves, but it only last a day or two.
The people on slaves ships had to lay in the prone position under the deck without any lights. They pissed, vomited and crapped were they lay and they had to keep laying in it until ships crews unshackled them. Slave ships had a high level of dysentery, small pox, lice and rats. If a slave was too sick or died then they were thrown overboard to the sharks.