for level flight lift is balanced by weight and thrust is

balanced by drag, hence then whole system become stable

w.r.t to force and for moments , inherently stable aircraft

are designed in a way that the pitching moment is balanced

by horizontal stabilizer , elevator may be deflected for

trim at certain velocities where i'm not changing the moment

curve slope , and for roll and yaw stability both aileron

and rudder may be used as they are cross coupled. Aids in

roll and yaw stability may be provided by high wing, sweep

back, dihedral wings etc