 Trim tabs come in two forms, adjustable and fixed.A fixed trim tab is manually bent to the required amount of deflection, while the adjustable trim tab can be controlled from within the cockpit so that different power settings or flight attitudes can be compensated for.Some large aircraft from the 1950s (including the Canadair Argus) used free floating control surfaces that the pilot controlled only through the deflection of trim tabs, in which case additional tabs were also provided to fine-tune the control to provide straight and level flight.