It would seem to me ( and yes I have an MBA) that the cab/waitressing gig is worse than a line job in a big corporation. At least at a big company there is room for advancement and exposure to other areas. That being said, I agree that Delta's current state of affairs might limit growth opportunity. Is a CSR job "visible" or is it just a mill?
I have never hired anyone based solely on the degree issue. It depends on the overall picture. If you have had to really work to get an education and only got three years of a degree then so be it. If your parents stroked a check ( like mine did

), then there is no excuse not to have finished IMHO.
Best of luck Columbia. You never know what the right thing is right away so give this a shot and see where it leads.