In the United States, what were the economic benefits of WWI?My report is on the innovations and economic benefits of WWI. I have many...

Assuming that you are talking about the United States, WWI
had two major types of economic benefits.

First, the war
improved the US economy in the short term.  The US had been in a recession when the war
began.  But that changed when the war started and the European countries started needing
things from the United States.  The European economies stopped working so well because
of the war and so they needed to buy from the US.  That led to a major boom in
business.

Second, the war made the US government and
industry work together more closely.  Some economists (see nber.org link) believe that
this helped lead to American prosperity even after the
war.

It is also worth noting that, after the war, the US
became a major player in terms of investing in other countries.  England had previously
been the biggest investor, even in countries like Mexico.  After the war, America's
economy was stronger than that of England and the US was in better position to invest in
other countries' economies.  This was also an economic benefit of the war for the
US.