A), I used to work for an airline, and B), most of my work since has involved commuting long distances.
Yes, most airlines have agreements with other airlines regarding passes for the employees of one to travel on the other. It's usually 'space available'. We were stuck one time in London for three days because there was no space available. Wound up packing everybody on a flight to MIA and, once in the states, I was able to finagle transportation home.
Depending on your status in the company, you may be able to wangle business passes. These are quite often also space available, but they don't cut into your allotment and are pretty much unlimited. Doubtful that the ramp rats, GA's, etc. had that option. I was sort of a professional class employee. so I commuted BUF-LAX every week for about 8 months. That's where I learned that even First Class (and it was a lot better in those days) gets old pretty quickly.
FA's and pilots often got 'must fly' passes, which means they had to be at the final end in order for a flight to leave. I think that was the only class that could bump revenue pax.
Since then, most of my work has been on a known temporary basis - that is, we all knew I wouldn't be working at location X for more than some relatively short time - say six months to one or two years. With a house and family at home, there was no way I'd move and then have to pack up and do it again. So, if I couldn't drive, I'd fly. Somewhat inconvenient, but I sure got a lot of miles and points out of the deal.
A lot depends on what your position is in the emploment strata. The suits get a lot of bennies while the hourly types have to make out as best they can.