US stealth jets never flown a serious mission to any heavily defended(with modern equipments) air space by a capable country.F117 is old technology, and shooting down one plane does not mean much if anything, stealth planes have flowen tens of thousands of mission and this is the only time one has been shot down. Seems to me flying tens of thousands of missions in to the most heavly defend space in the world and only one loss proves stealth is worth any price that has to be paid.
Even current stealth technology is not enough to penetrate so called "most heavily defend air space". Shooting down one plane that America bragged as undetectable and advanced, using old Soviet S-125 means much more and world community realized... "another gimmick"!! Shot down by 38 year old technology (S-125)!
F117 stealth technology literally came from Russia. America used Petr Ufimtsev theories on radar wave reflection and diffraction. Actually Soviets rejected Ufimtsev's model because of its poor flight characteristics. Search for "Lockheed credits Soviet theory in design of F-117".
"Ufimtsev taught at the University of California, Los Angeles (UCLA), which is the same school that Ben Rich, developer of the F-117 "Stealth Fighter", studied for his graduate degree" -Wikipedia.