Fault-tolerant flight control has the potential of improving the aircraft survivability in real life. This paper proposes an Incremental Backstepping Sliding Mode Control (IBSMC) framework for multi-input/output nonlinear strict-feedback systems considering model uncertainties, sudden faults, and external disturbances. This approach is a hybridization of the Sliding Mode Control (SMC) and a reformulated Incremental Backstepping (IBS). By virtue of the benefits contributed by both SMC and IBS, theoretical analyses prove IBSMC has less model depen- dency and enhanced robustness as compared to backstepping and backstepping hybridized with SMC (BSMC). When applied to an aircraft fault-tolerant control problem, numerical simulations demonstrate IBSMC can passively tolerate a wider range of model uncertainties, sudden actuator faults, and sudden structural damages as compared to backstepping and BSMC, using smooth control inputs with lower gains.