The other important keys are the Tab" sequences
In flight click the "Tab" key but do not hold it down.
A menu appears at the top left for a short time
Hit one of the keys listed and another menu appears, hit one of the keys and you get a result.

Example hit Tab 7 1 in quick succession and you will get a radio message directing you to the nearest enemy planes, both in sound and on screen text.
If you are escorting bombers and you lose them Tab 7 2 directs you to the nearest friendly bombers.

Here is the Tab 7 menu :



The various Tab 6 ... sequences give you several flight commands, including "target bombers", "cover me", and "drop tanks"

Check them out and note what they do.
You need to hit the keys very quickly, before the menus disappear