When you "flare" or "round out", you pitch the nose up slightly as you close the throttle in order to reduce your speed and rate of descent just prior to touchdown. The amount of pitch-up required primarily depends upon your airspeed and rate of descent, and it is usually only a few degrees. The slower the plane becomes, the more you have to pitch up. It is a smooth process and not hurried unless you misjudge and flare too late. In general, a 5 degree pitch up from level on the artificial horizon (attitude Indicator) would be about a maximum flare over a period of about 5 seconds. Doing it visually, without looking at the instruments, about the right amount of flare in a plane like a Cessna is when the top of the engine cowling appears to be about even with the opposite end of the runway (this is also how it looks in the real world). If you flare too quickly or too much, the airplane will "balloon" up in the air and you will find yourself too high without enough airspeed...a perfect recipe for a very hard landing or a stall followed by a crash. If you do balloon, don't over-react by abruptly pushing the nose over. You'll more than likely over-control and make things worse instead of better. Instead, gently bring the nose down to level, add a bit of power to get stabilized, then descend back to the runway and try it again. If you fly the Piper Cub, the pitch attitude when you land is exactly the same as it looks when you are on the runway prior to takeoff.

flare usually refers to when you pull slightly on the yoke just before landing so that your main wheels touch down first.

If you've ever watched a bird land you must have noticed it's tail feathers "flare" out just before it lands. On an aircraft it's more or less the same only the aircraft uses wing flaps which extend the width of the wing so there is more area to support the aircraft at very slow speeds, that and the angle of attack flare out like a bird does.

"Flare" is a technique used to land some types of aircraft.

The following is an attempt to provide a general description of the principles involved not the actual way it's done in any particular aircraft.

Imagine a longish tube with a gentle curve in it at one end. Hold, the tube at an angled downwards at roughly 3 roughly degrees from the horizontal with the curve at the bottom, on the ground but pointing upwards. Now, roll a marble down the tube. When it pops out of the end of the tube the marble will go upwards lose speed very rapidly and drop on to the ground with little or no forward motion.

Now, if you think of the tube as being the approach path to the end of the runway and the aeroplane as being the marble, I hope you get the idea of what is going on. The flare at the end of the approach is a way to slow the aeroplane down and dump lift so that contact with the runway is made firmly but, relatively, slowly.

The 'trick', as they say, is to get it right. Make the flare too soon (too high) and you hit the ground with a resounding, and possibly terminal, thud. If you don't make it sharp enough you will not get the aeroplane to 'stick' to the runway, because you still have too much lift, and you will 'float' down the runway. And, if you make it too late you hit the runway when you're still going down - and you don't want to do that!

Remember 'a good landing' is one you walk a way from, 'a brilliant landing' is one where you can use the aeroplane again!