My own verrrrrrry frustrating experience here: last fall, I was already boarded on a full flight leaving Albany NY. The pilot informed us that we’d need to deplane due to repairs. I had mere hours to call the hotel and cancel or I’d have been billed for a no-show.
So I got on my cell phone asap - NOT in airplane mode! Dang aids would not pair with the dang phone the entire time I was seated on the plane. The minute I got off the plane and into the terminal, they paired flawlessly and immediately. So call me clueless!
It appears that whether your aids are in Airplane mode or NOT, the bluetooth capability may be blocked by some kind of feature on the plane itself. If anyone out there has any insight as to what’s going on, chime in!