You get terrific travel benefits as an airline employee. If you are a flight crewmember and your company has agreements with other carriers, you can jumpseat on a fight with another carrier, meaning you can fly on that carrier at no cost if there is room for you. There are some restrictions and rules on jumpseating and strict protocols you have to follow. You also can fly on airlines at highly-discounted fares. These benefits extend to your family members. There are also passes and other arrangements for free or extremely-discounted travel for your friends.
I only have personal knowledge of Delta and United.
On Delta, you get unlimited domestic privilleges, 18 free transoceanic passes per year, and unlimited service free oceanic passes per year. You also get 18 "buddy passes". Your immediate family (spouse, dependent children) get the same benefits you do. You can also either nominate your parents or a "travel companion" for benefits which include 18 free domestic passes , unlimited domestic service fee passes, and 18 transoceanic service fee passes.
United has a similar system of "Write Your Own" (WYOs) where they issue you a ticket book and you simply write passes for yourself and your family. These are now free. However, it's been a few years, so you may want to check on the details of someone currently there for this one.
With US Air (I actually work for one of the red headed stepchildren wholly owns), we get unlimited travel on US Air for Wife, Children, and Parents for about $150.00 per year. This would be less for just yourself, or for yourself and wife. Also you can get travel on other airlines for 10% of full fare price (called ID90). Of course it is all standby travel. As a pilot you would be able to travel jumpseat on just about all airlines as long as you abide by the requirements. It all sounds great, but with FO pay at the regionals what it is and the wife working to make ends meet, there isn't much time for travel anyway.
Cargo carriers are a bit different. On Fedex, you can jumpseat on just about anybody, even though they are currently unable to reciprocate. You can also get ID-90's for you and your family, because FedEx gives other airline's employees a discount on space available shipping. I'm sure it's the same for UPS guys and gals. Also, any employee can jumpseat on UPS or FedEx, but not a pilots wife or kids. It's not bad, just a bit different.