In the Caribbean Air-to-Air communications by pilots (incl. US Airlines) flying over Piarco Airspace is on 123.45 and 123.4
Its interesting to hear AA, UA, ACA pilots communicate with one another and talk about their plans when they get back home! They also exchange flight condition reports at various levels.
122.75 is used for formation flights and practicing manuevers. Pilots call on this freq to announce their intentions or to talk to others in the formation. Many use it for an aircraft "CB" channel, but it is not supposed to be used that way.
if you are in an area like i am, where there is not an enormous amount of aircraft around, i just let the scanner search and lock out the freqs, that i know are the local airport approach/depature/tower etc, so i only get air-2-air comms...