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Congress can seldom be accused of moving too quickly, but that appears to be the case with the legislation that put air traffic controllers back to work after furloughs caused thousands of flights to be delayed.

The Senate and House passed the bill at a breakneck pace late last week. President Obama had planned to immediately sign it into law, but administration officials tell ABC News he's not expected to sign it until Tuesday - after a spelling error in the legislation is fixed.

The culprit, apparently, is a missing 'S' in the bill.

The legislation gave the Transportation Secretary the authority to shift $253 million to the air traffic control system from an airport improvement fund. The Senate rushed the measure through late Thursday night without a roll-call vote, followed Friday by a 361-to-41 vote in the House.

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The measure was pushed so quickly, parts of the legislation were actually handwritten, according to a copy of the bill obtained by ABC News.

The proceedings highlighted inconsistencies in the $85 billion across-the-board spending cuts known as sequestration. The rare bipartisan effort did not sit well with some members of Congress, particularly Democrats, who believe air travelers received special treatment, while deep spending cuts continued for other government programs.

With Congress out of town this week for recess, aides tell ABC News that a procedural correction will be made to the bill to send it to the White House for the president's signature.

Even before the measure was officially signed into law, the Federal Aviation Administration issued a statement saying that all employee furloughs had been suspended and normal operations had returned at airports across the country by Sunday evening.

So the case of the missing 'S' raises two questions: If lawmakers can act so swiftly to make frequent fliers happy - and to ensure their own flights are on time - can they move faster on other issues? And if the sequester can be tinkered with on this matter, is it really as dire and as inflexible as it once seemed?