Sitting at the beach in NYC with my Pro-106 in search, heard pilots (?) talking about "doing 3 k but I don't want to end up in the ocean" on 140.175 and then another reading out descending altitude down to 3500; some other chatter on 140.2 am. Just starting to get into milcoms so I don't know what I'm hearing.
You're hearing what's known as the "interplane" channel used by a flight of (assumably military) aircraft. Usually a lot of BS'ing but also some important comms between themselves. They can then use the normal 225-400MHz band for official comms with their controllers -- ATC, AWACS, NORAD, etc.
138-144 & 148-150.8MHz is the spectrum to check for this sort of stuff, AM mode & in 25kHz steps. In some situations where they might be communicating via secure means on 225-400Mhz, by habit, they sometimes continue to talk in non-secure mode on their VHF channel. Keep in mind this spectrum is also used in FM or P-25 mode (12.5kHz steps) for US military & federal government land mobile radio nets, though depending on where you live, the only usual agency you might hear in FM/P-25 mode is the USAF's Civil Air Patrol. You can also hear a satellite on about 150.00MHz.