The most convincing argument I've heard is centered around just how much cash flow and expenses goes through the airlines on a daily basis, meaning they'd need some extraordinary amount of cash in the bank to weather something unprecedented like this. If they _did_ have that much cash, it'd be bad for the economy since that capital is effectively "locked up". Instead, give the proceeds back to the shareholders that will likely do something else with it - invest in new businesses, buy more goods and services, etc. I don't have any links handy, but Ross Perot railed against companies hoarding cash for decades.