Missing Corrie McKeague slept under bin bags, using them “almost like a blanket”, on a night out two years before he disappeared, an inquest heard.
The airman vanished mysteriously in the early hours of September 24, 2016.
He is presumed dead by police and the search for his body was called off in 2018.
McKeague, from Dunfermline, Fife, had a severe drinking problem and his family requested an inquest into his disappearance, which is currently underway.
The gunner’s best friend Paul Robb, who served with him in 2 Squadron in the RAF, told the inquest that McKeague often passed out and “woke up in unusual places”.
He recalled a story where the Scottish airman slept under bin bags after a night out, when they were on a medic course in November 2014, nearly two years before he vanished.
On the third day of the inquest at Suffolk Coroner’s Court in Ipswich, Mr Robb said: "He told me that he slept under some bin bags.
"I can't remember if he told me they were full of rubbish. They were outside a coffee shop or something like that, round the back where the bin area was.
"He described it as almost using the like a blanket to stay warm."
McKeague had a drinking problem, partly stemming from events in his youth, it was said.
His father had previously spoken to The Mirror ahead of the fifth anniversary of his son's disappearance.
After his parents’ divorce he found the body of a close friend who had been hit and killed by a train.
In his witness statement, Mr Robb said: "Corrie had always been extreme with his drinking and there were no half measures with Corrie.
"When he drank to extreme, he was a very exaggerated version of himself. He was very outgoing, very extroverted and loved to talk to people."
He added his friend had once “downed a whole bottle of red wine in 17 seconds”.
Alongside his drinking, he had suffered with mental health issues, and Mr Robb said his mental state was often “up and down”.
He had previously received counselling and been prescribed antidepressants.
On drunken nights out, it was not uncommon for McKeague to wake up in unusual places, like a McDonald’s bathroom, or a bench outside a Tesco.
On one occasion, Mr Robb said that during a stag weekend a few months before he vanished in Liverpool, he climbed a drainpipe to get into the accommodation he was staying at, but ended up in the wrong room, where he fell asleep.
Mr Corrie also revealed how Corrie had gone on an RAF trip to Uganda and South Sudan when airmen were forbidden from going out drinking, but he broke the rule and was sent home.
Despite his drinking, he said that he had never seen his friend being aggressive or getting into an argument.
McKeague vanished on a night out in Bury St Edmunds, Suffolk.
He had slept for two hours in a shop doorway after being ejected from a nightclub and was last seen by a CCTV camera going into a bin area behind shops at 3.25am.
Suffolk Police believe he ended up being tipped into the back of a Biffa bin lorry after climbing into a Greggs bin to sleep.
Even after a £2million police inquiry his body was never found.
Sergeant Ross Stevenson who was McKeague’s former line manager, said: "He's a friendly lad, cheeky I would say, but he was a good laugh, he was capable, he just needed channelling, I would say."
He said in a statement that Corrie was a "nightmare on the drink" and "he liked to be steaming".
Sgt Stevenson recalled once seeing the airman walking along a road, one mile from the airbase, at around 10am and stopped to give him a lift.
He said: "Corrie was walking along the verge of the road and still wearing the clothes from the night before. Presumably he had been on a night out."
Sgt Stevenson added that Corrie had previously asked for help with his finances, and asked for his card to be kept in a locked box for a month.
"He came to us asking for help as he had no money for food or anything," he said.
He said the base arranged for meal tickets for him to ensure he was fed and discussed how to pay off money he owed.
William Hook, the doorman at Flex nightclub, where he went missing, said he felt no cause for concern when Corrie arrived at the club on the night he disappeared.
But when he saw him at around 1am, he saw that the airman "struggled to walk without holding onto anything around him".
He added: "That was the point I clocked him, I suppose. I said: 'I think you've had enough mate, shall we go out the front?'"
The doorman said Corrie co-operated and left the venue, describing it as an "easy ejection".
Mr Hook added: "He was a popular lad around the town, he knew a lot of people who were out, he would go round groups of people speaking to groups of people and saying hello to staff."
The inquest continues.
