Boeing have just released the following article which I reproduce below, together with a couple of pictures. I find this interesting as it looks like the latest development of the X-36 ie. a "Tail-Less" Aircraft.

ST. LOUIS, October 18, 2002 – Boeing [NYSE: BA] today unveiled the "Bird of Prey," a technology demonstrator that pioneered breakthrough low-observable technologies and revolutionized aircraft design, development and production. The once highly classified project ran from 1992 through 1999, and was revealed because the technologies and capabilities developed have become industry standards, and it is no longer necessary to conceal the aircraft's existence.

In addition to proving many new stealth concepts, the Bird of Prey program demonstrated innovative rapid prototyping techniques. Developed by the Boeing Phantom Works advanced research-and-development organization, the Bird of Prey was among the first to initiate the use of large, single-piece composite structures; low-cost, disposable tooling; and 3-D virtual reality design and assembly processes to ensure the aircraft was affordable to build as well as high-performing.

Fully funded by Boeing, the Bird of Prey project costs $67 million. A subsonic, single-seat technology demonstrator, the aircraft completed 38 test flights as part of its flight-demonstration program. Its first flight took place in fall 1996. Bird of Prey has a wingspan of approximately 23 feet and a length of 47 feet, and weighs nearly 7,400 pounds. Powered by a Pratt & Whitney JT15D-5C turbofan engine, the Bird of Prey has an operational speed of 260 knots and a maximum operating altitude of 20,000 feet.

"Early investments in technology demonstration projects such as Bird of Prey have positioned Boeing to help shape our industry's transformation," said Jim Albaugh, president and CEO of Boeing Integrated Defense Systems. "With this aircraft, we changed the rules on how to design and build an aircraft, and what we've learned is enabling us to provide our customers with affordable, high-performing products. Projects such as Bird of Prey have provided the catalyst for integrating speed, agility and reduced cost into the processes we employ to introduce new commercial and military systems to market."

Boeing's current development of the X-45A Unmanned Combat Air Vehicle, or UCAV, technology demonstrator draws directly on its Bird of Prey experience. Some aspects of the UCAV's innovative radar-evading design, such as its shape and inlet, were developed from this project. Together, Boeing Phantom Works and Boeing Integrated Defense Systems are developing UCAV for the Defense Advanced Research Projects Agency, or DARPA, and the U.S. Air Force.

"The success of the Bird of Prey is a testament to the shared commitment of Boeing and the Air Force to pioneering innovative methods to drive down costs and improve performance," said George Muellner, senior vice president of Air Force Systems for Boeing Integrated Defense Systems. "This project stressed affordability as much as performance and quality, and is one of many that we are using to define the future of aerospace."

Human Made High Technology is being presented as an explanation for "disappearing aircraft" witnessed by myself and other researchers studying persistent contrails. One must consider both prosaic explanations and exotic Defense R&D before concluding what some report seeing is taken as conclusive evidence of alien technology.

Electrochromatic panels (tiny video sensors) on the skin of aircraft is one such exotic technology which could explain as least some of the sightings reported.

It might be enlightening to visit the Project Chameleo/Richard N. Schowengerdt's website which presents papers, videos and drawings explaning some of the more recents research projects conducted by research scientist and the Air Force...
http://members.aol.com/rschowe173/chameleo.html and take a look at the following patents:

In addition see the follwing articles on Camouflaging as stealth tech:

Electrochromatic Panels in May, 1997 POPULAR SCIENCE article)
GROOM LAKE TESTS TARGET STEALTH (Aviation Week of February 5, 1996, pp 26-27, by David A. Fulghum/Washington).
While it is possible that many experimental missions and varying atmospheric conditions are occuring in our atmosphere and that stealth tech/camouflage undoubtedly is being developed, one must ask the following questions: What would be the purpose of using such stealth tech (if economically and technologically feasible) in non-combat situations in the skies above populated areas? If it is feasible, why would it be necessary? Who are they hiding from?

And if it is indeed human-made technology in use and in some way connected with the creation of persistent contrails, why cloak the aircraft and forget about the billowing emissions stretching out for miles behind?
Perhaps one explanation for my sighting of a blinking out "craft" and its persistent contrail is the experimentation of 'emissions cloaking' along with aircraft camouflage. Much R&D is taking place in radar jamming and emissions control...but why would our military be testing or using such cloaking devices over a populated area in mid day?

Again: Who are they hiding from?

I also wanted to address a comment Gordon Scott made regarding sightings of disappearing planes in his article "Disappearing Planes: Not An Off-The-Shelf Technology" appearing at http://sightings.com/general3/disaa.htm
"I have been following the various reports of the disappearing planes and have yet to find an observer who said "I was watching it with binoculars, never took my eyes off it for a moment, and it just blinked out and is totally gone".
It is evident that Scott has not seen my report on a "craft" and its miles-long persistent contrail that winked out as I was watching it through binoculars last December. (see report below)

Certainly it is most important that observers who feel they have witnessed a disappearing aircraft to consider that aircraft can make sudden moves --shifting in altitude and direction. In addition, clouds or obscuring haze (particularly what we are seeing out there now apparently resulting from persistent contrails) and lighting conditions can appear to change the color and reflectivity of craft traveling through the atmosphere.
What I witnessed was in a clear blue sky and I was intensely watching this "craft" and its dashing persistent contrail through binoculars coming toward me.

Though I feel that witnessing this event is a rare occurence (I have spend hundreds of hours skywatching over the last year and a half and have only witnessed a 'wink out' of a PC aircraft before me one time) -- I certainly will be out watching with video camera in hand in hopes to capture this event on video. And I encourage other researchers and the public to do the same.

Regarding Disappearing Aircraft And Human Technology...
While I think it is very probable that our government has developed much stealth and camouflage technology, there are a few things that this explanation of disappearing aircraft does not take into account... "aircraft" which apparently disappear along with their persistent contrails being one of them.
Myself and others have witnessed not only something looking like an aircraft suddenly and inexplicably vanish before our eyes...but have witnessed the craft and its miles-long persistent contrail vanish simultaneously.

One of these startling events took place on 12/23/99 at 8:10am CST near Lake Lewisville, TX just north of Dallas. My account is as follows.
The Not So Persistent Contrail...
During the last part of December 1999, I decided to go out into my unfenced yard which ajoins a wooded area and lake to do a bit of skywatching. The day before this particular day I had seen many persistent contrails...as well as some very peculiar looking multiple contrails with no apparent craft in front of them.

It was a cool morning with a few clouds to the southeast--otherwise a fairly clear sky. As I watched to the east, I spotted an aircraft flying east just south of my position creating a broad white persistent contrail at about 15,000 feet. I noted a very slight haze in that area of the sky but had no trouble seeing this craft clearly through my 10x50 binoculars.

Just as this aircraft moved out of view into the cloud bank to the southeast -- I spotted what I thought was another aircraft spewing out a persistent contrail moving from the southeast toward me taking a NW heading. The contrail behind this apparent aircraft was broad but fairly thin as compared with the other one just formed and seemed to be on an upward incline.

What I saw in front of this persistent contrail appeared to be oblong but had no distinct shape, no glints from the sun and looked more dusky pink than white or silver. I watched this object intently through my binoculars noting that the persistent contrail "cut out" on occasion leaving a blank space a couple of times in the clear blue sky.
I kept thinking that it would "clarify" as it got closer. This one was higher by 10,000 feet but I had seen other aircraft that morning in the same area which were very distinguishable and identifiable.

As this object was to the ESE moving within range for identification, its contrail stopped and started repeatedly.
This particular contrail had to be many miles in length with breaks.
Suddenly, while I had the object and part of the persistent contrail in sight with my binoculars -- the object or aircraft inexplicably disappeared-- blinked out totally not to return