Sounds like you may have seen a YB Flying Wing. It was the predecessor to the stealth planes. Looks like a pair of sissors flying across the sky.
I too saw what I thought was a UFO over Whidbey Island. It looked just like the stealth bomber, but it had a bow like shape instead. But then, years later, I saw the first steath bomber after its existence was released to the press. I realized that what I had seen must have been a prototype.
In truth, I don`t think the powers that be are doing a very good job of hiding such things from the public. The Air Force Base near where I now live has SR-71s, and they don`t seem to care that people know about it. They don`t fly during the day of course, but I have seen them at dawn and dusk.

To the other fellow that posted a follow up. You saw a lizard, plain and simple. Perhaps it was one you had never seen before, and thus, you assumed it was some kind of alien.

I am not saying there are no UFO`s. In fact, I firmly believe there is alien life and that they have visited our planet. Even I have seen things I can`t explain. I have seen technology that our world will probably not achieve for for thousands of years. My point to all fellow believers is this: It would be wise to be a little more discriminating about what you choose to believe. Do the research. Make yourself a little more credible, by ruling out all other possibilities. Don`t just go and tell everybody that you saw a UFO. Nothing is done for the cause, by making oneself look like a cultish nut. With friends like that, who needs enemies?