GENEVA—The world’s airlines will carry a record number of passengers and earn all-time high collective revenues in 2018, IATA economists forecast. Briefing journalists Dec. 5 from the IATA headquarters here, chief economist Brian Pearce said it was expected that the global airline industry’s net profit in 2018 will increase to $38.4 billion from the $3.5 billion expected for 2017. Collective revenues will be $824 billion in 2018, a 9.4% increase over 2017’s $754 ...