In relative terms, this question has a rather broad scope, so I will attempt to answer it more broadly (albeit tactically) rather than on a case by case basis. I’m also going to narrow the scope a bit by focusing on World War II, although this should be (at least somewhat) applicable to The Great War as well.

The book Fighter Combat: Tactics and Maneuvering by Robert Shaw is likely the best codified and most complete book we have to date (in the public realm) on air to air combat - not just in the modern era but also in regard to guns-on-guns dogfighting (e.g. World War II).

Generally, though, being able to visually identify friendly aircraft and communicate with them would not only be a basic part of training but also understood to be absolutely essential to survival. Formation flying, especially (and the hand signals that go with it), would likely help train (or weed out) young pilots very quickly in regard to avoiding contact with friendly planes. (Here is the Navy’s FTI manual for T-45 Goshawk formation flying )

If you were a British Spitfire pilot flying during the Battle of Britain, for example, you would likely be able to readily identify friendly aircraft like the Hurricane, Mosquito, Blenheim, Lancaster, etc. relative to non-friendly aircraft like the Me-109, Ju-88, Stuka, etc.

Between visual identification and the need to communicate with (at least) your immediate friendly aircraft in order to have any realistic chance of success, the odds of being shot down by enemy aircraft were likely orders of magnitude more likely than colliding with a friendly one.