In the 1930s, it was the PWA which built tons of long-lasting infrastructure including the Hoover Dam and many substantial other projects;

https://en.wikipedia.org/wiki/Public_Works_Administration

That was probably the best use of funds at the time since there was broad based unemployment among a largely unskilled population. This time around, it seems like it's mostly service businesses that are struggling so it's not so clear what the best use of labor would be..