Branson is the founder of the airline and owns 51% stake, with the remainder owned by US rival Delta, which on Thursday said it would not inject cash to save Virgin.
Earlier this week, Branson told staff he offered his private island home Necker as security against a government loan to save the airline, as the travel sector has been wiped out by the coronavirus pandemic.
“Now you have Virgin Atlantic owned by Delta and a Caribbean island-based, non-resident billionaire,” O’Leary told Sky News.
“Frankly if he’s worried about Virgin he should write the cheque himself. It’s not like he’s short of money.”
Branson has been widely criticised for seeking governmental help considering his US$5.9bn estimated paper fortune.
“Virgin Atlantic is ridiculous… This is Branson’s second go at trying to fleece the British taxpayer.”
— SkyNews (@SkyNews) April 24, 2020
In an interview with the Financial Times on Thursday, O’Leary dismissed a call for airlines to leave middle seats idle as “idiotic” and said governments would have to pay the fares, or it won’t fly.