Big news in the U.S. ultra-low-cost-carrier market this week, as Spirit and Frontier announced their plans to merge. Meanwhile, Allegiant's long-serving CEO Maury Gallagher, who helmed one of the most profitable airlines in the world, announced his retirement. Madhu Unnikrishnan and Edward "Ned" Russell. discuss the hurdles ahead for the merger, why Gallagher's retirement is significant, as well as why India's IndiGo is not concerned about a revitalized Air India.