How formal is it in the flight deck during operations? eg, are you addressed as Captain / Sir, and like wise downwards. When back at the hotel, are you just a group of people recovering in your own ways and 'painting the town together?
I've flown with Captains who must have been given that name on their birth certificates. They were, to a man, total tools.
My mother calls me John. That's how I introduce myself, and I'm quite happy to be called that by all. The pilots often refer to Captains as skipper. I have no doubt that if I need to make them jump, that I can do so irrespective of how informally I run the coughpit.
The company requires cabin crew to refer to the Captain as 'captain', when in front of passengers. Skipper is pretty common there too.
Off duty....well I guess that varies across airlines. These days, going your own way is much more common than it was in the past. We never even see the cabin crew on slips...mostly they stay in different hotels.
I recall, many years ago, flying with a particularly unpleasant Captain. A pretty young hostie bounced into the coughpit, and said, "I'm xx_X, what are your names". So, the engineer was Fred, I was John. And the Captain, well he was captain. At which point, pretty young thing bounced out again. The engineer, then commented, "Jeez, skipper, your mum must have hated you".
Speaking of engineers.... One commented:
"Hey, skipper, when we get to Singapore, you'll have to get a new engineer".
"What? Why?"
"'Cos, I'm not flying with an cough**** like you again."
They were a different breed.