How Are Unions Different from Welfare?

Labor unions have been a great boon to workers. There is no denying that in the 20th century, workers were at a tremendous disadvantage and needed something like unions to achieve some basic rights in the workplace.

But unions didn't stop at leveling the playing field; they just kept demanding more and more, and they have managed to tip the balance strongly in their favor.

Now we have the United Auto Workers (UAW) demanding that, for example, the U.S. federal government bail out the American auto manufacturers so that union jobs can be protected. The auto manufacturers hardly seem to even want the bailout: they would rather go into bankruptcy protection so they can get out of the crippling union contracts.

I'm not saying that the car manufacturers are wonderful, or that they aren't at least partially responsible for getting into this mess in the first place. But why should the government pay to protect jobs that the industry doesn't want? Isn't that just welfare?

Wouldn't it be cheaper for the American taxpayer to just give welfare checks to the UAW workers instead?