Key TakeawaysHilton reported second-quarter earnings that missed analysts' estimates and trimmed its full-year earnings outlook.Revenue for the second quarter was slightly ahead of projections as Hilton's revenue per available room rose.The results came as earnings from Airbnb, Tripadvisor, and Hyatt Hotels this week raised concerns about softening travel demand. Hilton Worldwide Holdings (HLT) reported second-quarter earnings that missed analysts' estimates and trimmed its full-year earnings outlook amid c ...