I worked in the aerospace industry for 8 years supporting the launch industry at Cape Canaveral and Vandenburgh AFB. I left aerospace to get a better job in industry. Aerospace generally pays slightly less and gives you less real world experience IMHO than other industry areas. I've been working for a chemical industry company for 10 years now.
1. Did you have to get a license or any other type of certification beyond a college degree?
No - I had a BSME, never got my PE, and found it fairly easy to get an aerospace job. Also, although an MS or PhD may make it easier to get a job, I think there are fewer places you can find those jobs. You become more speciallized which means there are fewer companies that will hire you and fewer opportunities. Luckily that's compensated by the fact there are fewer people going after those jobs and you can always take a job that would otherwise be filled by someone with a BS so the end result is that you can find a job more easily.
2. What are some of the stresses or hazards, if any, that someone in your field of works might experience?
Being laid off. The aerospace industry lives and dies on large contracts. When we had an Atlas rocket go into the Atlantic, the project shut down for almost a year. The second Atlas to go in about a year or two later left us all wondering if the doors would be open the next day. While in that program, the engineering department I was in went from 120 people to less than a dozen. When they finally closed that department I managed to get onto another large program that was just starting up, but had that other program not been there, I'd probably have been laid off too. Aerospace runs the risk of regular lay offs, the pay isn't as good, the work is often less challenging and I've found that industry values novelty and individualism more than aerospace.
3. What would you say are the average number of hours you work a week?
About the same as industry, 45 to 50, sometimes more, sometimes less.
4. What kind of degree or other forms of education did you pursue in order to prepare for your career?
None. BS is sufficient and a PE is less important in aerospace than in industry.
5. Would one need more educational training or certification to get a higher position in your industry? If so what kind of training or certifications would that person need?
Depends on what you mean by "a higher position". Unfortunately, most companies don't have genuine 'technical' ladders. They are all managerial ladders. The company I'm in now claims to have a technical ladder, but it really doesn't exist like a managerial ladder. If you want to 'rise to a higher position' that generally means going into management, something I refuse to do. I enjoy the technical aspects way too much and refuse to do administrative or managerial work. If you stay in the technical side of the business, then there are many things you can do to promote yourself technically including taking both in house and externally run technical courses such as presented by ASME and many others. Taking short courses (week long or less) works out well and are paid for by the company. If you want to rise to 'a higher position' in a technical field without going into managment, you need to do things such as obtaining patents, presenting original technical papers on your work at conferences, taking professional courses and other things. I'd also suggest getting a few very good mentors early on in your career no matter what you want to do or where you want to go.
6. What are some basic skills that could help someone looking to enter your occupation?
That's a rather broad question. Perhaps more than anything, you need to really enjoy what you're doing. The more you enjoy it, the easier it will be to excel.