The data presented have been obtained from accelerometer VG and VGH records mainly from subsonic transport aircraft in scheduled operation. Curves present the average distance flown by aircraft, with and without cloud warning radar, at various altitudes up to 55 000 ft before experiencing a positive or negative gust of 10 ft/s. Details of all the aircraft flight histories are tabulated. Also presented, are curves of relative frequencies of gusts of various amplitudes at different altitudes (the equations for these curves are given) and the gust alleviating factor as a function of aircraft mass parameter and aspect ratio. A simple method outlines how the user may compare the flexibility of the aircraft wing with that from which the data have been obtained (the expressions used are fully discussed). An example illustrates how the curves may be employed to compile cumulative frequency gust spectra for an aircraft wing.