Struggling airlines almost always go into chapter 11 bankruptcy, to restructure their debt and create new labor contracts. There is also chapter 7 bankruptcy, which deals with liquidation. Airlines do not make up for their losses through taxpayer dollars.
Chrysler and GM were not allowed to go into chapter 11 bankruptcy, which probably would've helped their businesses a great deal. Instead the bondholders got screwed in favor of the unions (this is another discussion entirely). Even so, they were provided a loan by the government, they aren't owned by the government. Although taxpayer money was used for the loan, taxpayers aren't on the line every year to make up for GM and Chrysler's losses (at least not yet).
Amtrak is owned by the government, in the same way as the US Postal Service. Both operate with massive amounts of losses every year. A legitimate business would be forced to declare bankruptcy, but due to government ownership, they use taxpayer money to make up for their losses in order to remain in operation.
High Speed Rail will be another massive government-funded black hole if allowed to go through. Taxpayers will be on the line every year to make up for its losses, not to mention the original building costs. Unless of course you're naive enough to believe that the government can generate a positive return on it.
Furthermore, California High Speed Rail is one of the most corrupt projects I've ever seen. One can only assume other high speed train efforts will mirror it.
