HAVE BLUE was the code name for two Stealth technology demonstrator aircraft built by Lockheed's (in)famous Skunk Works around 1980. They were the first flying stealth aircraft; however, they didn't have much in the in the way of systems (no weapons, comm gear, etc.). They were the direct precursors to the YF-117 prototypes, and look like a 1/3 to 1/2 size version of the stealth fighter but narrower, and, as chronoso reminds me, their vertical stabilizers angle in towards the centerline instead of outwards like those on the F-117. Their delta wings are swept back more sharply, as they don't have bomb bays or any of the large internal systems that must fit inside the operational F-117 body.

There were two HAVE BLUE aircraft. Both flew at Groom Lake (Area 51), although the media will only say they flew at a 'secret testing facility in Nevada,' and were probably responsible for some of the Area 51 sightings made around 1980. They were completely unlike any aircraft then known, as they were the first designed using nothing but flat panels and straight edges - their shape was dictated by the requirement to keep a low radar cross-section.

Although the HAVE BLUE team was sure of the plane's design as it applied to the radar cross section, no one had yet tried to make the ungainly thing actually fly until then. The HAVE BLUE was fully fly-by-wire, as (like its younger and larger brother the F-117) the HAVE BLUE is dynamically unstable in the air and requires computer support to remain controllable.

One fun factoid: most of the work done on the F-117's stealth characteristics, which rely more on shape and design than materials, was based on a publication by a fairly obscure Soviet physicist who had extended Maxwell's equations to describe electromagnetic reflection off surfaces and edges.