They do create more lift throughout the entire range of velocity. However, it is important to remember--the airplane can still stall--it will just stall at a somewhat slower airspeed. Also, it is important to note that flaps increase drag--greatly increase drag. Therefore, if your engine is dead, don't deploy the flaps--your plane will stop and fall straight to mother earth. Also, if your engine dies on glide slope, pull those flaps up, or the same will occur.....