Seventeen Boeing 737 pilots were exposed to an acute stressor in a flight simulator: a birdstrike between V1 (velocity of aircraft on take-off run at which crew is committed to take-off regardless of any incidents occurring) and VR (velocity of aircraft at take-off). Certain physiological variables together with state anxiety scores were measured at different stages of the simulated flight. Levels of plasma cortisol, norepinephrine, total protein, total lipid, lactate, and the haematocrit changed significantly across the test conditions. Plasma epinephrine, osmolality and glucose levels did not change significantly across the test conditions. Captains and copilots differed significantly in the profiles obtained for the state anxiety scores. The variables measured in this study demonstrated different profiles in response to the stressor. Conceptual and methodological problems need to be solved before an integrated psychophysiological approach to the reactions of pilots to stressors can be developed.