While a lot of airlines charge you a yearly fee (Delta=$50) to non-rev, certain companies (AMR) charge you a fee per flight if you have less than X years seniority. This DOESN'T apply if you sit in the actual jumpseat, but their gate agents are trained to not give you a jumpseat pass unless there is no room in the back...i.e if there's room in the back, the agent is supposed to put you as a non-rev, and you're charged a service fee.

In commuting from SJU to Arizona, this worked out to close to $200 a month, and that usually was jumpseating half the time. It was $40 for SJU-DFW and $20 DFW-TUS if I didn't sit in the jump. Sometimes I got lucky and they'd give me a jumpseat pass with room in the back, but it was somewhat rare for gate agents to agree to that.

This was effective for all AMR flights, including Eagle. Nothing like paying $30 for MIA-BNA on your own airline.