U.S. carriers on Tuesday said travel demand has roared back after a blip caused by the Omicron coronavirus variant and would remain strong enough to help them offset a run-up in fuel costs with higher fares. Atlanta-based Delta Air Lines Inc. said it was seeing an “unparalleled” increase in demand, resulting in the highest ticket sales in the company’s history last week. “We’ve not seen a stronger demand … in my career,” Chief Executive Ed Bastian said. Rivals United Airlines Holdings and American Airlines also said the demand is higher than it has ever been. In an encouraging sign for the industry, United said business traffic is rebounding more quickly than expected. As a result, carriers now expect their revenue in the quarter through March to be stronger than what they estimated in January. United, for example, said its quarterly revenue would be near the higher end of its forecast, …