I know you've gotten a lot of input but I noticed there were some things not covered so I wanted to give you some more info.
My DH is currently active duty military. He retires this year after nearly 21 years of service. While in college, he got his private pilots license. The idea of flying airplanes for a living made him really happy. However, when you look into the time and effort it takes to become a pilot for an airline it is ridiculously expensive. To build up enough flying hours, take courses to get your pilot rating, etc, you are easily looking at a $40K investment. To get your pilot rating can cost between $10K & $15K. It is not cheap. When faced with this, DH decided that if he was ever going to become a commercial pilot he would have to be a military pilot first. When he joined the military, pilot slots were very difficult to procure. At the time, they had such a limited number of people they were taking to train to fly. Today is a completely different story.
DH got into the Air Force and the reason being is because of all the cargo planes the AF flies that are similar to commercial airplanes (C-5, C-17, C-130, KC-10). DH has flown C-130's his entire career and loves that airplane. It's the workhorse of the military. When his original commitment was nearing he did start interviewing for airlines and never got hired so he decided to stay in. It's actually a good thing because his commitment was up in August of 2000. Many of our AF friends who left the AF about the same time and were hired by airlines lost their jobs just a year later when 9/11 happened. They were low man on the totem pole and were the 1st to get cut from the pilot pool. Many of them were never rehired and have found other jobs.
If your son decides he wants to fly airplanes and goes into the military after college he will have a 10 year commitment before he can choose to leave to go to the commercial airlines.
We have a few friends that work for airlines. One of our closest friends works for Southwest and loves the company. When he started flying for them nearly 10 yrs ago he was gone a lot, especially the holidays. Pay starts at right around $32K to $35K. In essence a brand new airline pilot is working doctor's hours for about a 1/3 of the pay.
To get hired by companies such as Fed-Ex and UPS, you have to know someone who flies for them and can put in a good word to get hired. The more people or pilots you know at those companies, the better your chances for being hired. From what I have heard, they will not hire you otherwise.
People have asked DH as he gets ready to retire what airline he's going to work for and he's said none. As much as DH loves flying, he no longer wants to do it for a living. He's not interested in the low pay and long work hours. More than anything he's not interested in having to be gone from his family all the time. He feels he's missed enough already. Our kids are still young. I married DH 5 years into his military career and it took us another 7 1/2 yrs for our 1st child to be born. Our kids are 7 and almost 3. DH was 2 months shy of 40 when our youngest was born. So that's something else your son will have to think about. If he values family and time with them, the airlines might not be for him.
I wish I could give you insight on benefits. From what I know, our friend who works for Southwest has good health insurance, 401K, etc. That's one of the reasons Southwest was the only airline he would work for. I don't know for a fact how often family gets to fly free with the airlines. I've heard conflicting things. Some allow immediate family to fly whenever they want, other airlines limit the number of times. I know that a friend of mine's dad who works for Delta was able to fly fairly often but she was flying standby. She never had a guaranteed seat until she was actually on the airplane. So if she couldn't get on one flight, she'd have to wait for another one. Not sure if this is still the case.
I know I threw a lot of info at you but I hope it helps.