Code for Airplanes (and cars and other safety critical applications) follows a special set of rules in order to eliminate wonkiness that tends to crop up in complied programs (usually the result of undefined behavior, not always the programmers direct fault).

See: http://blog.regehr.org/archives/213 (particularly part 3)

http://blog.llvm.org/2011/05/what-every-c-programmer-should-...