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Washington — House lawmakers could face challenges returning to Washington this week to vote on a package to fund the government as the shutdown disrupts air travel. House Speaker Mike Johnson said Monday morning that he would call members back to the Capitol "the very moment" the Senate holds a final vote on a government funding package. Members will be given a 36-hour notice, Johnson said, a change to earlier guidance that said lawmakers would have 48 hours to return. Johnson, a Louisiana Republican, told reporters he wants the House to vote "as soon as possible" on the deal that would fund the government until Jan. 30. But air travel delays and cancellations around the U.S. could upend the House vote. House Republicans can afford to lose only two votes if all members are present and voting. Any absences could muddle the math and prolong the shutdown fight. Two Republicans voted against the original version of the bill when it cleared the House on Sept. 19, though it also had the support of one Democrat. Johnson called the travel disruptions, which have been largely caused by staffing shortages, a "very serious situation" and urged members to begin heading back to Washington immediately. "As of Sunday, nearly half of all domestic flights and U.S. flights were either canceled or delayed," Johnson said. "I'm stating the obvious to all my colleagues — Republicans and Democrats in the House — you need to begin right now returning to the Hill. We have to do this as quickly as possible." More than 1,000 flights around the U.S. have already been canceled in the coming days, according to FlightAware.