I tend to agree that it was a big consumer of computer cycles but I also have my doubts.  After I wrote a Column in Computer in December 2006 on the Univac Service Center for the Petroleum Industry in Dallas, which famously lost money and closed in the early 60s, I received a a small torrent of emails from retired petroleum engineers who felt that they were finally receiving their due.  As Jonathon noted, they were doing high dimensional fourier transforms and lots of linear programming, which consumes lots of cycles.  I received emails from an  Esso engineer, who noted that they took delivery of the first Univac 1103 in '56 and had von Neumann as a consultant.  I also got a note from a Chevron engineer who told me about the work he did in the early 60s.  At the same time, if you look at the companies buying large machines in the 50s, 60s, and early 70s you find that aerospace firms out number petroleum firms.  

Unless other evidence is out there, I tend to accept the thesis that the aerospace industry was the lead consumer of computers with petroleum behind it.