flextime vs overtime

I mentioned ages ago that some firms abuse their entry-level workers by underpaying them, having them work near-continuously, and then not paying overtime.

But what about flextime? Instead of earning overtime, you earn the chance to have more time off. When I first heard of that option, I thought, "Great! More vacation!". I would happily give up a significant chunk of money for more time off. Hell, if it weren't impossible in my own working situation and culturally impossible without having offspring (oh, and there's that whole pesky health insurance), I'd work part time.

But flex time doesn't work that way, at least in the consulting world. Instead of "work hard in the field, take lovely vacations", it's "work hard for as long as we tell you, and then when we decide there's no work for you, then you can go home." I guess that can work, although when it was presented to me, it made me think long and hard about the company's viability. What if I spent two or three years building up a spectacular backlog of flextime and the company went belly-up? It makes sense for construction-type firms that have genuine off-seasons, but in my experience, if the weather gets bad and the fieldwork gets slow, that's when you write the reports to tide yourself over.

I do have some experience with other, non-consulting flextime (government work or other fields altogether), and it works out more the way I'd like it to - work longer hours now for fewer hours a reasonable time later. But can I find this in environmental work in the US?