US travellers lamented news of the shutdown of Spirit Airlines on Saturday, saying that the closure of the ultra-low-cost carrier eliminates one of the few air travel options for low-income and working-class Americans. Spirit abruptly cancelled flights overnight, stranding passengers and staff around the US, Caribbean and Latin America, after collapsing under financial pressures that included a sharp rise in fuel costs due to the Iran war. On social media platforms such as Reddit and X, where disgruntled passengers often vent their frustrations about delayed or cancelled flights, former Spirit patrons recounted how the airline had provided a lifeline to money-conscious travelers. "They truly were one of the last cheap -- 'get me there as fast and cheap as possible' -- options," Reddit user AioliUpset7805 wrote on a thread about the airline's closure.…