Just a question? Why do pilots like light knives and hand guns? Does it make a difference pulling high Gs or are they fitted not to apply force to the body in flight?
Because a cockpit is a pretty confined space and you're not gonna be able to fit an intact M4A1(or GUU-5P) in there, but they dont do that because the pilots purpose if hes shot down is to escape and evade. Not to confront the enemy and eliminate him, a pistol is a defensive weapon (with the notable exception of the Mk23 mod. 0 SOCOM which is an "offensive handgun") and its compact and easily fits into their survival kit and used only as a last resort. Their knives are not long for a second reason; they aren't made for specificially for killing enemy soldiers their made for survival. Hope that helps :-D
* Forgot to add that because they are both small and compact they're lighter so its easier for the Pilot to move without expending energy lugging around extra weight.