On the fly Meaning, Definition & Usage

  1. adverb on the run or in a hurry
    • she wrote those letters on the fly

WordNet


Definitions
  1. (Baseball), still in the air; said of a batted ball caught before touching the ground. (b) at the moment needed, without prior preparation. said of objects created as needed in the course of some activity, rather than having been prepared before the activity began. A term Much used in computer programming. (c) busy; in motion..

Webster 1913