[P/O W. 'Moggy' Cattermole]

Erm, leaning around to see the sights on planes like the 109, press shift F1; to get the iron sights on certain aircraft instead of the reflector sights, such as the P40 or Zero Fighter, you have to have your reflector sight shot up first -- when a bullet disables the reflector sight, the iron sights will automatically move into position.