Recently a saw Saving Private Ryan and the showed the presence of flame thrower during the beach assault. I made some research and i discover in a book that in an "assault boat team" there was a flamethrower.
This thread has an answer for you, provided by /u/Caedus_Vao: https://www.reddit.com/r/AskHistorians/comments/26owvo/how_accurate_is_the_dday_omaha_beach_landing/