High ambient temperatures increase the wing-beat frequency in flying locusts, Locusta migratoria. We investigated parameters of circuit and cellular properties of flight motoneurons at temperatures permissive for flight (20–40 °C). As the thoracic temperature increased motoneuronal conduction velocity increased from an average of 4.40 m/s at 25 °C to 6.73 m/s at 35 °C, and the membrane time constant decreased from 11.45 ms to 7.52 ms. These property changes may increase locust wing-beat frequency by affecting the temporal summation of inputs to flight neurons in the central circuitry. Increases in thoracic temperature from 25–35 °C also resulted in a hyperpolarization of the resting membrane potentials of flight motoneurons from an average of-41.1 mV to -47.5 mV, and a decrease of input resistances from an average of 3.45 MΩ to 2.00 MΩ. Temperature affected the measured input resistance both by affecting membrane properties, and by altering synaptic input. We suggest that the increase in conduction velocity Q10=1.53) and the decrease of membrane time constant (Q10=0.62) would more than account for the wing-beat frequency increase (Q10=1.15). Hyperpolarization of the resting membrane potential (Q10=1.18) and reduction in input resistance (Q10=0.54) may be involved in automatic compensation of temperature effects.