Ventajas
The defense industry is stable, and the work is interesting. You'll never run out of questions about your job at cocktail parties. You can always find projects you can sink your teeth in, and you'll work with some enthusiastic and smart people. You can become an expert in something very few people can do -- build aircraft. There is plenty of opportunity to make a good living for you and your family. If you have hobbies and/or community involvement, you can usually flex your working hours to accommodate them.
Desventajas
You're not going to get rich. Or recognized in a satisfying way for that matter. Some people receive rewards, usually not more than a couple hundred dollars, because they made the company tens of thousands (or even millions) of dollars. The aforementioned enthusiastic and smart people are often pursuing other avenues like a side business or education, 1) because they can and 2) they realize the limitations of working in a huge corporation. Also, as a Gen Xer, I feel the pinch from both generations beside me. The company is hiring tons of college graduates because they're cheap and we need a workforce when the baby boomers retire, and the baby boomers dominate the workforce as it is. I don't see a promotion into leadership for at least 5 years, maybe longer with this ridiculous stock market.