Clint Eastwood and Steven Spielberg collaborated on bringing the book Flags of Our Fathers to the big screen. The book was written by James Bradley (with Ron Powers), son of John 'Doc' Badley, and tells the story of the six men - of whom 'Doc' Bradley was allegedly one (see further on this, below) - immortalised in Joe Rosenthal's famously iconic flag-raising photo, taken atop Mt. Suribachi, on the island of Iwo Jima.
Hayes, along with John Bradley, is one of the core trio, rounded out by PFC Rene Gagnon, who are brought home and fêted as heroes, to be utilised, in conjunction with Rosenthal's iconic image, as means to raise war-bonds.
This is akin - but here as more of a central narrative plank - to the segment of the Hanks/Spielberg Pacific series in which John Basilone, another hero of Iwo Jima, is brought home to help raise war revenues. Basilone, as depicted in that series at any rate, tired of the hero role, requesting that he be sent back to fight (and to die, as it turned out) with his buddies.
Of the three men depicted in Eastwood's movie, it's Ira Heyes who has the greatest struggle adjusting to post-combat life, and in particular the idea of himself as a war hero.
 With a projected budget of $80 million, the film actually only cost $55 million.