Meghna Maharishi talks about how United Airlines' (UAL) earnings performance will hinge on the resilience of wealthy travelers, a key demographic driving revenue for premium and international segments. The industry watches for potential domestic upside from Spirit Airlines' (SAVE) uncertain future, which could see a merger with Frontier Group Holdings (ULCC) or Chapter 7 bankruptcy. While United has historically been more optimistic than Delta Airlines (DAL), its earnings call is expected to largely align with Delta's conservative tone.