It's certainly possible since Bitcoin don't care what medium you uses to communicate with other nodes. For people who curious about what's OP talking about, you can check it at https://www.unblock.news/news/bitcoin-lightning-payment-radio-waves

Mesh network also can be used to broadcast bitcoin transaction. A twitter user, Coinsure did that few months ago.
You can check this twitter at https://twitter.com/Coinsurenz/status/1052022462790033408 or https://zerocrypted.com/bitcoin-offline-transactions-are-now-possible/ for more explanation.


IMO it's good enough to see possibility of broadcast bitcoin transaction without directly connected to other nodes or use internet as medium.