Surging jet fuel prices, driven by Middle East tensions, represent the dominant catalyst pressuring U.S. airline balance sheets and elevating bankruptcy probabilities for several carriers through year-end. JetBlue faces the steepest near-term challenge, with analysts projecting potential 2026 losses exceeding $1.3 billion at current fuel levels around $4.50 per gallon, which could push debt toward $9 billion and annual interest costs above $800 million. Frontier and Allegiant carry moderate exposure tied to high lease obligations and limited premium revenue streams, while major carriers like American maintain stronger cushions. Spirit Airlines’ recent decision to cease operations after two Chapter 11 filings underscores how quickly liquidity can evaporate without successful restructuring or government support. Traders are monitoring upcoming fuel price trajectories, debt covenant compliance, and any additional carrier announcements that could shift implied probabilities before December 31.