Frontier Airlines is exploring a renewed bid for Spirit Airlines, people familiar with the matter said, as Spirit continues discussions with bondholders over the terms of a potential bankruptcy filing.

If a deal between the two carriers is reached, it would likely happen as part of Spirit restructuring its debt and other liabilities in bankruptcy.” While any potential merger is purely hypothetical and would run into the same antitrust concerns and roadblocks as with the JetBlue takeover,

Spirit Airlines shares are surging in premarket trading Wednesday on a report that Frontier Group Holdings is in the early stages of a renewed bid for its rival discount carrier.