My understanding is that no tax money ever goes to the PBGC. It is funded solely by the airlines/companies that use it. Those companies pay a premium each month, per employee, that insures their pension.
Much like the money that's in your bank or credit union is federally insured, the PBGC is backed by the federal government if it fails. But it hasn't failed yet, so none of your tax money has been used.
It's all here if you want to read the facts:
http://www.pbgc.gov/
Abe44
