Today's local paper (St.Paul Pioneer Press) has an article on the MN state legislature just approving $10 million towards adding a second Amtrak train between the Twin Cities and Chicago. If all continues to go well, it will start in 2024. Biden's infrastructure plan also includes reinstating trains from the Twin Cities to Duluth - Superior.
Earth's atmosphere is 78% nitrogen, 21% oxygen, everything else is a 'trace' gas making up the remaining 1%. However, hydrogen is more common than helium; it's believed part of the reason the Hindenburg burned the way it did was the US wouldn't sell Nazi Germany helium so it had to use combustible hydrogen.
In any case, the difference between a blimp and an airship is the construction, not the gas. A blimp is basically a big balloon with gas inside it; an airship has a rigid frame with large pockets inside for holding gas.
