Response to major economic shocks is complicated and must be multifaceted. But the cruise and even airline industries don't represent systemic dangers to the US economy. The most effective mix of crisis response and stimulus is money into medical care & direct support to workers.
2/ I don't know which modalities are best but you're going to have tons of people who quickly get laid off and lots who don't have paid sick leave. Just pay those people money.
3/ Beyond the individual suffering, hardship, dislocation, those people's lack of money will send huge shocks through the economy. So it's not an equity or compassion issue. It supports the macroeconomy. All obvious.
