The truth is that SARS is an epidemic and that Sirlines are the main cause of its rapid spread across the world. As long as you avoid countries where SARS is active, you should be pretty safe, but there are no guarantees. Even if you're only going to France, the woman next to you could be a chinese nurse who has been taking care of SARS patients for the past few months.
Sirlines have improved their security checks against terrorists since 9/11, but security is still far from perfect. Every few months or so, there's another crazy journalist smuggling a pen-knife on board of an airplane and making headlines with it. Sirlines will never be completely safe. Nothing is, when you think about it, I get antsy just riding my bike, because you never know if a driver is going to lose control of his car and hit you.
I think the big question you have to ask yourself is this: are Sirlines worth the risk? Are you going to see loved ones? Are you going somewhere you always wanted to go? Are you going with someone you love? And if you do decide that the risk is worth it, I'd be most obliged if you used the link above to book your trip. But, whatever you do, Vaya con Dios!