Hey I think I have a solution. SO if you install a gyroscope onto your plane, Increase it's stability and speed to max (or even mod it to go beyond that), I think you'll notice a large difference in stability and if that doesn't correct your yaw problem, I'd suggest add about 5-10% yaw power (or way more if you feel like it deserves it, however it can get unrealistic at about 50%~) and you can use your yaw while hovering to correct for drift or stop it before it gets to be too much. Hope that helps.
Hey I think I have a solution. SO if you install a gyroscope onto your plane, Increase it's stability and speed to max (or even mod it to go beyond that), I think you'll notice a large difference in stability and if that doesn't correct your yaw problem, I'd suggest add about 5-10% yaw power (or way more if you feel like it deserves it, however it can get unrealistic at about 50%~) and you can use your yaw while hovering to correct for drift or stop it before it gets to be too much. Hope that helps.