From the above the capitol... blog:
Posted by Maj Paul Cianciolo on 11 October 2009 filed in Aircraft Operations, Emergency Services, Radio Communications
"The International Civil Aviation Organization (ICAO) and the FAA have changed Civil Air Patrol’s aircraft callsign to “CAP” instead of “CPF or CAP Flight.” The new callsign should be used in air/ground communications and when filing flight plans. All Civil Air Patrol personnel should discontinue the use of “CAP Flight” immediately and use “CAP” only.
"The pronunciation of the new “CAP” callsign is exactly how it sounds — as in “baseball cap.” It should be used along with the appropriate wing aircraft number, i.e., “CAP 2561.” This new callsign should also be included in the remarks section of all FAA flight plans."
So aircraft in Civil Air Patrol effective immediately will no longer use "CAPFLIGHT" as a callsign. Instead they will use CAP (pronounced as in baseball cap) followed by a number. This is per a policy letter from CAP National Headquarters dated 11 October 2009.
You can read the CAP NHQ letter at
http://www.ohwg.cap.gov/CAP%20Call%20Sign%20Ltr.pdf
