Dec 31 (Reuters) - Thousands of flights within the United States and internationally were delayed or canceled on Friday, adding to the travel disruptions during the holiday week due to adverse weather and rising cases of the Omicron coronavirus variant. Over 3,090 flights were canceled globally as of early Friday evening, including nearly 1,550 flights within the United States or entering or departing it, according to a running tally on flight-tracking website FlightAware.com. There were over 8,650 global flight delays in total. The Christmas holidays are typically a peak time for air travel, but the rapid spread of the highly transmissible Omicron variant has led to a sharp increase in COVID-19 infections, forcing airlines to cancel flights as pilots and crew quarantine. The sudden arrival of Omicron has brought record-setting case counts to countries around the world. Transportation agencies across the United States are suspending or reducing service due to COVID-19 staff shortages as the Omicron variant surges nationwide. The number of new COVID-19 cases in the United States has doubled in eight days to a record high of 329,000 a day on average, according to a Reuters tally. Over that same period, the number of hospitalized COVID patients rose 32% and hit a record high in Maryland, Ohio and Washington, D.C. On Thursday alone, 23 states, Puerto Rico and Washington, D.C. set pandemic records for new cases, according to the Reuters tally. The state of New York reported over 74,000 COVID-19 cases on Thursday from more than 336,000 tests at a 22% positivity rate, Governor Kathy Hochul said. New York said last week it will sharply limit the number of people it allows in Times Square for its New Year"s celebration, which culminates with the dropping of a giant crystal ball at midnight, signaling the start of the new year. "We reduced the density of the crowd. This is a safer way to proceed," Tom Harris, the president of Times Square Alliance, told CNN on Friday. New York City Mayor-elect Eric Adams will be sworn in after the ball drop. Some critics, however, have raised concerns over the celebrations going ahead at all, given the high positivity rate. The rise in U.S. COVID-19 cases has caused some companies to change course from earlier plans to increase the number of employees working from their offices starting next week. Chevron Corp (CVX.N) was to start a full return to office from Jan. 3 but told employees this week it was postponing the plans to an unspecified date. U.S. airline cabin crew, pilots and support staff are reluctant to work overtime during the holiday travel season despite offers of hefty financial incentives. Many workers fear contracting COVID-19 and do not welcome the prospect of dealing with unruly passengers, some airline unions have said. In the months preceding the holidays, airlines were wooing employees to ensure solid staffing, after furloughing or laying off thousands over the last 18 months as the pandemic crippled the industry.