That depends on where you are based. As far as the standard flight benefit, it's only on JetBlue. Other airlines depend on whether they're a JetBlue partner and whether that partnership agreement includes employee nonrev travel. If you're based at a major airport, there will also be airport specific station agreements.

As for other airlines, as an airline employee that is a member of the industry group, you'll have access to ID90 tickets, which are standby tickets at up to 90% off the regular fare on all member airlines (Also called a Zed fare). Most major airlines are in this group. Just be aware that when nonreving on other airlines, you will be given the lowest standby priority.