123.45 - better than Safetycomm for air to air
Although of somewhat dubious legality, 123.450 Mhz has become the de facto air to air frequency for the ‘same way / same day’ type formation flying. As mentioned above, the range of VHF signals can be quite extensive. I recall hearing crews on two ‘Heavy’ aircraft discussing where they were going to eat when they got in to Singapore. From the conversation they were somewhere over the Middle East at the time, we were heading up the East Coast of Germany…
It’s preferable to use 123.45 instead of Safetycomm for air to air. Safetycomm is proving a really good idea amongst the farm strip fraternity, even in the crowded South East of England. It does get busy with legitimate traffic and can do without the air to air stuff.