Spirit Airlines is reportedly heading toward bankruptcy. Insider sources revealed on Tuesday that the airline is filing for bankruptcy protection following the collapse of merger negotiations with Frontier Airlines. Read more: Trump’s Tariff Talk Sends UBS Lowering China’s Growth Outlook to 4% These sources indicate that Spirit is currently engaged in extensive talks with creditors to formulate a bankruptcy plan that would secure the support of the majority of its lenders. The airline is expected to file for bankruptcy within the next few weeks. Despite strong travel demand, the low-cost carri…