The co-owner of struggling Virgin Atlantic Airways Ltd. said it’s unable to invest more and raised the possibility that Richard Branson’s U.K. airline could face going through insolvency proceedings.

Delta Air Lines Inc., which owns a 49% stake in Virgin Atlantic, can’t help out because it’s consumed with its own problems and it’s already bumped up against U.K. limits on foreign airline ownership, said Ed Bastian, the U.S. company’s chief executive officer, in an interview with CNBC.

“With our crisis in cash, we need to protect our own business. That’s where our focus is,” Bastian said. “I trust Virgin will work through its challenges with the government. If they are required to go through an administration process in the U.K., I’m confident they could re-emerge.”

The blunt commentary offers a window into the peril facing Branson, who’s swiftly become the highest-profile victim of an airline-industry crisis that’s only just getting started. Virgin Australia, another carrier he founded, entered administration this week after failing to obtain a state bailout, and beleaguered Virgin Atlantic has struggled to overcome resistance to its request for hundreds of millions of U.K.-backed loans.

Read more: Branson Looks to Caribbean Island to Help Save Virgin Empire

In a statement, Virgin Atlantic said it remained in a “stable position.” The carrier is exploring “all available options to obtain additional external funding,” while acting to “reduce costs, preserve cash and protect jobs.”

Branson’s Virgin Group controls the Crawley, England-based carrier, and has said it lacks the resources to get through the coronavirus pandemic. The entrepreneur is struggling to convince governments to rescue his brands given his own highly visible wealth and long-time residency in the West Indies, which has led him to be viewed as a tax exile.

Virgin Atlantic said in an email that its discussions with stakeholders are constructive. Branson has offered to invest some $250 million in Virgin Group companies, and said he would offer his Necker Island estate in the Caribbean as collateral.

While restructuring is possible under the U.K.’s administration process, it more often leads to insolvency than Chapter 11 bankruptcy in the U.S.

Britain has yet to decide on Virgin Atlantic’s weeks-old application for hundreds of millions of pounds in support. The government has asked the airline to provide details of its efforts to seek private-sector funding and hired Morgan Stanley to assess its profitability, viability and contribution to the U.K. economy, according to people with knowledge of the matter.

Delta acquired the stake in Virgin Atlantic in 2013 to boost its stake in the lucrative market for trans-Atlantic travel. The Atlanta-based carrier said Wednesday that it plans to slash expenses to conserve cash. It’s raised $5.4 billion in capital since early March, and has secured an additional $5.4 billion in payroll support from the U.S. Treasury Department.

The spread of Covid-19 has had “a devastating impact on our business,” Bastian said in a letter to employees.