I believe the idea that the airline is in danger of nationalisation is credible. After all the trains buses and tube system are effectively being Government funded with very few passengers. Various countries eg Germany are taking equity stakes in exchange for funding.
Once Brexit takes place IAG will have to be broken up if BA is going to be allowed to function freely in the U.K. It is planning to sell Waterside so clearly it is in a deep hole as the cash raised, assuming it is saleable, is only going to be minimal
The UK will need a national carrier with the two contenders Virgin and EasyJet unable to provide the complete coverage needed. What might make the Government pause is the potential for an almost financial bottomless pit