U.S. stock index futures rose on Tuesday, extending a strong start to the year after worries about the Omicron variant of the coronavirus subsided and travel stocks bounced. Equity markets across the globe bounced for the second straight day of trading in 2022, with the World Health Organization saying more evidence is emerging that the coronavirus variant is affecting the upper respiratory tract, causing milder symptoms than previous variants. Travel stocks led premarket advances with a 2.7 percent rise in Carnival Corp. leading gains among cruise operators, while American Airlines gained 0.9 percent. Big technology stocks that led gain in the previous session also rose, with Apple Inc., Tesla Inc., Meta Platforms Inc., Netflix Inc., and Amazon.com Inc. gaining between 0.3 percent and 0.9 percent. Ford Motor Co. added 1.5 percent after the automaker said it will nearly double annual production capacity for its red-hot F-150 Lightning electric pickup to …