Part I: Travel statistics. National & state travel statistics ; City-by-city tourism & spending ; City-by-city travel survey ; Most-visited cities ; Most-visited tourist attractions ; International travel--inbound ; International travel--outbound ; Economic impact of travel -- Part II: Business segments. Airlines ; Airports ; Auto rental ; Buses & motorcoaches ; Convention centers ; Cruises ; Hotels & resorts ; Peer-to-peer accommodations ; Rail travel ; Tour operators ; Travel agents ; Timeshare ; Vacation homes -- Part III: Destinations. Beaches ; Cultural districts ; Distilleries & wineries ; Entertainment destinations ; Great places in America ; Hiking & backpacking destinations ; Historic communities ; Historical sites ; Islands ; Mountain destinations ; National historic & scenic trails ; National scenic byways ; Parks--city ; Parks--national ; Parks--state ; Spas & wellness retreats ; Wonders of the United States ; World Heritage Sites -- Part IV: Analyses. Adventure travel ; Agritourism ; Business travel ; Domestic travel ; Dog-friendly hospitality ; Family travel ; Golf travel ; Hunting & fishing ; Leisure travel ; Online travel planning & booking ; Recreational vehicles ; Road travel ; Scuba travel ; Ski travel ; Sports travel ; Spring break ; Student & youth travel ; Tourist activities ; Travel rewards programs ; Traveler shopping ; Traveler segmentation ; Vacations -- Appendix A. Academic centers -- Appendix B. Academic programs -- Appendix C. Analysts -- Appendix D. Associations.