 One specific failure in the massive operation was the critical lack of transport aircraft for the operation , an unsolved flaw that had dogged every large @-@ scale airborne operation the Allies had conducted . In the original planning for Varsity , an extra airborne division , the 13th , had been included ; however , a lack of transport aircraft to drop this division led to it being excluded from the final plan . Thus , the unsolved problem of a shortage of transport aircraft meant that a third of the planned troops to be used were discarded , weakening the fighting power of the airborne formation . In the event , the airborne troops actually employed were sufficient to overwhelm the defenders . 
