Only Bombers (currently B-17) and Transports (currently C-47) have a external view.
The view keys are per default set to:
F1 - cockpit
F2 - interior view
F3 - external view
F4 - chase view
F5 - point view (camera stops at current plane position)
F6 - bombsight (B-17 only)
F7 - snap view (view keys on numpad 'snap' into position)
F8 - pan view (view keys on numpad move head around
F9 - instant view (no transition between head movement change)
Default view is (obviously) F1 + F7.
You can change views with numpad keys; also you can change head position with arrow keys and save that position with F10 key.
For further information the game play section on the AH site is highly recommended.
Az
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Azrael
Red Dragons