Merriam-Webster Collegiate Dictionary - flying

 I. adjective  Date: before 12th century  1.  a. moving or capable of moving in the air  b. moving or made by moving rapidly ~ feet a ~ leap  c. very brief  2. intended for ready movement or action a ~ squad car  3. having stylized wings — used especially of livestock brand marks  4. of or relating to the operation of aircraft a ~ club  5. traversed or to be traversed (as in speed-record trials) after a running start a ~ kilometer  II. noun  Date: 1548  1. travel by air  2. the operation of an aircraft or spacecraft