Travel stocks drop on Omicron-related flight groundings Dow up 0.98%, S&P 500 up 1.38%, Nasdaq up 1.39% Dec 27 (Reuters) - The S&P 500 index (.SPX) ended at a record high on Monday, its fourth straight session of gains, as strong U.S. retail sales underscored economic strength and eased worries from Omicron-driven flight cancellations that hit travel stocks. U.S. retail sales increased 8.5% year-over-year this holiday season, powered by an ecommerce boom, according to a Mastercard Inc report, giving the S&P 500 retailing index (.SPXRT)a boost. read more Travel-related stocks, typically sensitive to coronavirus news, declined after U.S. airlines canceled about 800 more flights on Monday after nixing thousands during the Christmas weekend, as Omicron cases soared. read more The S&P 1500 airlines index (.SPCOMAIR)shed 0.57%. Cruise operators Norwegian Cruise Line Holdings (NCLH.N), Royal Caribbean (RCL.N) and Carnival Corp (CCL.N)fell 2.55%, 1.35% and 1.18% respectively, among the biggest decliners on the benchmark S&P 500. "The market is in this interesting place where we have a strong consumer, with spending up 8% year over year. Personal consumption makes up 70% of our GDP, and that remains flush," said Sylvia Jablonski Kampaktsis, chief investment officer and co-founder at Defiance ETFs in New York. "Omicron reminds us that we still exist in this corona ecosystem. And it"ll probably be one of many things that we will continue talking about with this virus but the doomsday COVID scenario of 2020 feels like it"s far behind us." All 11 main S&P 500 sector indexes advanced, with energy (.SPNY) and tech (.SPLRCT) leading percentage gains. The Dow Jones Industrial Average (.DJI) rose 351.82 points, or 0.98%, to 36,302.38, the S&P 500 (.SPX) gained 65.4 points, or 1.38%, to 4,791.19 and the Nasdaq Composite (.IXIC) added 217.89 points, or 1.39%, to 15,871.26. The S&P 500 has climbed 4.9% during its recent run of gains, its biggest percentage gain over a four-day period since early November 2020. The Nasdaq Composite (.IXIC)got a boost from megacap companies, including Tesla Inc (TSLA.O), Microsoft Corp (MSFT.O), Apple Inc (AAPL.O) and Meta Platform (FB.O). Main U.S. stock indexes are on track for a third straight yearly gain, with the benchmark S&P 500 (.SPX) poised for its best three-year performance since 1999. Volume on U.S. exchanges was 7.76 billion shares, compared with the 11.74 billion average for the full session over the last 20 trading days. Advancing issues outnumbered decliners on the NYSE by a 2.29-to-1 ratio; on Nasdaq, a 1.09-to-1 ratio favored advancers. The S&P 500 posted 58 new 52-week highs and no new lows; the Nasdaq Composite recorded 101 new highs and 145 new lows.