B-2 Spirit

The B-2 is a strategic bomber currently in service with the US Airforce. Its big, its mean and its very expensive. It is also one of the most (if not the most) advanced military aircraft in the world today. The overall design of the B-2 has strong ties to Jack Northrop's 'flying wing' designs of the 1940s. Obviously technology today is far more advanced than it was 60 years ago and the B-2 boasts (amongst other things) no less than 130 computers with over 2 million lines of software code (lj has pointed out that this isn't really a lot of when compared to other aircraft of the time)

Type
Strategic, long-range, multirole bomber
Power Plant
Four General Electric F118-GE-100 Turbofan engines rated in the 19,000-pound thrust class
Top Speed
High subsonic
Crew
Two (Pilot and Mission Commander)
Range
6,000+ nautical miles unrefueled
10,000+ nautical miles with one refueling
Combat Ceiling
50,000 feet
Takeoff Gross Weight
336,500 pounds
Armament
40,000+ pounds; can deliver a variety of conventional and nuclear weapons, including near precision-guided munitions, gravity bombs and maritime weapons.

NUCLEAR                       CONVENTIONAL                   PRECISION      
16 B61                          80 MK82		       8 GBU 27
16 B83 			     16 MK84                      12 JDAM
16 AGM-129 ACM        	     36 CBU87                     8 AGM-154 JSOW
16 AGM-131 SRAM 2               36 CBU89                     8 AGM-137 TSSAM 
		              36 CBU97

The B-2 is a 'low observable' or stealth aircraft. Basically this means that is very hard (in some cases damn near impossible) to track it on radar and other sensors. The theory is that if you can't see it you can't shoot it, and if you can't shoot it you can't kill it. It is this technology that allows a relatively large aircraft such as this to reach targets over enemy territory and return home despite it's lack of combat or maneuvering ability. The B-2's low observability is derived from a combination of reduced infrared, acoustic, electromagnetic, visual and radar signatures. Many aspects of the low-observability process remain classified; however, the B-2's composite materials, special coatings and flying-wing design all contribute to its "stealthiness."

All of this comes at a cost of course...a little research indicates a per unit cost of between $750 million and $1.3 billion US dollars. Despite this, 21 such aircraft have been manufactured and are currently stationed at Whiteman AFB, Missouri. Of the 21 only 2 were built to final specifications and the remainder have since been upgraded to meet air force requirements.

The first B-2 was publicly displayed on Nov. 22, 1988, when it was rolled out of its hangar at Air Force Plant 42, Palmdale, California. Its first flight was July 17, 1989 and the first operational aircraft, 'Spirit of Missouri', was delivered Dec. 17, 1993. B-2s have taken part in Operation Allied Force and Operation Enduring Freedom with missions of up to 44 hours duration. Notably, In support of Operation Enduring Freedom, the B-2 flew one of its longest missions to date from Whiteman to Afghanistan and back.