If he needed money to fund his working time machine...
Why didn't he use the device itself to increase his bank account? A time machine is the ultimate money making device. I can see if we needs money if his time machine ISN'T WORKING YET. But it works great. The minion Gencorp guy in the pink suit even makes a comment that they could go back in time and put money in the bank and become millionaires off the interest. Why does chin man instead work with an evil CEO and gov't contractor who makes weapons? Why take on a boss with a lot of strings attached when you can be self-sufficient and self-funding?
I know we wouldn't have a movie, but sheesh... a guy smart enough to make a time traveling plane can't work such a simple money/funding concept out?