Before we begin talking about launching paper airplanes and the different kinds of flights they make, a word of warning is needed. Some of the airplanes in this website have very sharp noses when folded properly. Please be careful when launching these or any paper airplane since their flights can be very erratic. When flying them indoors make sure to warn all people around you before launching. When flying them outside on a breezy day even by yourself, you should expect the unexpected.
In the beginning throw a new plane level, gently and at a slight up angle. Throw jet, darts, and higher speed craft level and a bit harder once they’re trimmed.
A good way to launch a glider or a plane that floats is almost straight up. These planes will usually flip at the top of their path and float a long distance before reaching the ground. An acrobatic style craft can be thrown toward the ground. Trimmed correctly many planes will loop the loop at least once before falling.
Most paper airplanes fly poorly at first. The most likely reason is that the craft is not folded properly. Remeber that all creases should be tight, accurate and very symmetric. A plance may have to be folded several times before it will fly well.
If a well folded plane still stalls when launched, it has too much left. Try adding some down elevator at the back of the wings or tail. If the plane tends to dive, there is not enough lift and some up elevator is needed. If it rolls to the left or right, check the dihedral angle and the symmetry of the wings. If it simply flutters to the ground, there is too much drag. Make sharper creases and perhaps tape down parts which impede air flow. Sometimes the addition of a paper clip or staple near the nose turns a poor flyer to a good one.