What are the mechanics of aircraft flares?

I've often seen jets release their flares in dogfight or against ground threats.

How does that happen?

Are choppers able to do this, too?

Does the aircraft do it automatically like in COD: Black Ops, or would I have to press a key?

If yes,

• Which key?*
• What is the strategy behind it? Against what kind of threats is it useful?
• When exactly should I release it?

*: I'm playing on the PC, but console info would be nice, too, for the sake of completeness.

Solution 1:

Flares are the first unlock for both choppers and jets.

To activate flares, you must press the "x" key (default for PC, right bumper/r1 is default for consoles), after which, there will be a short cooldown before they can be used again.

Flares work to stop missiles that are tracking you, from continuing to track you.

The best time to use them is when a missile is in mid flight, not before it is launched, otherwise they'll just wait for the flares to dissipate before firing.