"JetBlue’s move is aimed at either forcing a termination of the deal or restructuring it at a new purchase price", said Steve Segal, M&A attorney at business law firm Buchalter.

"Segal said mounting concerns about Spirit’s finances and its future might be deemed to constitute a “material adverse effect,” offering JetBlue a legal argument to call off the deal without triggering the July extension."

Likely a new price or walk away...guessing the former.