External views for fighters (with a few exceptions) would be totally realistic. The idea a pilot in combat is only "aware" of what can be seen from his cockpit, is total nonsense. The advent of radios in airplanes eliminated this problem. If you can be seen by other friendlies, you would know what the enemy is doing. Especially how the enemy is maneuvering against you.
However. Most AH pilots are playing a video game, instead of trying to create a military airwar simulation. They freqeuntly neglect to share information or give timely warnings to other planes on their side. How many times have you heard someone complain about only getting a "Check 6" warning, after their plane is in flames ?Is this a realistic simulation of air combat in the real world ? No. It is not.
I can only think of a few exceptions. Some pilots do fly and hunt alone. The "Lone Wolf" scenario. Damaged planes sometimes fall behind or are seperated from friendlies. Planes out of ammo fly away. Radios are sometimes "shot out". Simply put, if you are close enough to friendlies to be seen, and your radio equipment is undamaged... You should have EXTERNAL VIEW. Suddenly all the personalities and incompetancy of the VIDEO GAME culture are eliminated, And the game becomes more REALISTIC.