Another interesting play would be if spirit was securing financing to buy frontier. Wouldn’t that be a curveball. Instead of 52/48 ownership percentage in favor of F9.. swap those and spirit become 52% owner .. end result is the same . The two airlines that want a marriage get one.
Both board of directors would approve .. it would be essentially be the same deal and then the shareholders don’t Matter ..

robins only play would be then to try a hostile bid for frontier.. and indigo I believe is major shareholder there and would never allow it.