Let me see if I can chime in with a little helpful criticism. I do this for a living, so take everything with a grain of salt, as I am picky. 
First off, fantastic photos. I absolutely love them as I have a thing for aviation in general. I would love to be able to get some of the up close opportunities you have had.
Down to business.
Meta tags - simply put, you have used too many. Most modern search engines will start to ignore them after about 10, as well as possibly even blacklist you for attempting to "cheat" the system. Google is notorious for this.
The nav - You have images for nav with ALT text, search engines will not pick up on these much of the time, and can leave parts of your site unspidered. Add alt text to these, pretty simple and can make a big difference. Also, the site layout is professional, but the nav images are not. I would try and figure out another way to style these without the glow, etc. Just a personal preference here, but it's from lots of experience.
Flow - the design changes from page to page in some sections. References or home vs contact for example. There appears to be 3 different layout styles going on. Choose one layout and stick with it. I would choose with the look you have for contact (again, personal opinion). It just seems simpler and cleaner.
Also, make sure to set your content box to a min height. It gets very small on certain portfolio pages that only have 1 row of images.
Besides that It's a good site. I especially like the portfolio page.