Northrop Grumman B-2 Spirit
AKA the 'stealth bomber' and famously the most expensive aircraft ever built at up to $2.1 billion apiece ($2.8 billion at today's values). Capable of dropping 16 nuclear bombs in a single pass, plans to build 132 were scaled back to just 21, one of which crashed on takeoff in 2008.
The 20 survivors have seen action on numerous occasions, being used in the skies above the former Yugoslavia to drop bombs on Serbian forces as well as over Iraq and Afghanistan. Whilst secrets about its systems are naturally well-guarded, B-2s have appeared at air shows and to great acclaim.