Yes, the Navy stopped stockpiling helium (which is a by-product of natural gas) when they decided they didn't need it for blimps any more.
Thanks for letting me know, that.
I didn't know that! I always send a balloon whenever I send anyone flowers for something.
I didn't know until recently either.
Helium is one of the lightest gas. So whenever it gets a chance, it escapes into the outer space. Once it gets there then humans can't catch it back to the Earth.
Yes, that is correct. But additional helium is produced underground by alpha decay of radioactive materials.