Make a killing off
In Band of Brothers WWII miniseries one of the guys said:
"There's gonna be good times. When we get home, I mean. First thing I'm gonna do is get my job back at the cab company in Frisco. Make a killing off all those sailors coming home, you know?"
What is "make a killing off", what does it mean?
It means to make a lot of money.
He sees business increasing due to all those sailors coming home and he wants to to drive his cab overtime to take advantage of the increased business.