Correct (Score 2, Informative)

Absolutely. The stability of the plane is in large part to do with the angle the wings make with the fuselage. Upward pointing dihedral wings are far more stable, but offer less maneuvrability. Anhedral wings, on the other hand, make the plane aerodynamically unstable, thus allowing it to turn far faster. It's pretty intuitive really. A dihedral (upward sweeping) wing, is lengthened horizontally when the plane turns (because it's tipped towards the horizontal) therefore generating more lift and righting the plane. An anhedral wing, on the other hand, is shortened when the plane banks, further reducing the lift on the banking side, and accelerating the turn. Anhedral winged planes are essentially impossible to control without computer aid. Hence they are restriced to fighter planes and such...