Tyrone Lock, from Hope under Dinmore in Herefordshire, was found 48 hours after reports he was acting erratically at Macdonald Hill Valley Hotel near Whitchurch in Shropshire.
The 18-year-old had taken ecstasy and the herbal stimulant khat before fleeing in his socks and boxer shorts.
West Mercia Police said it would "review future callout procedures".
CCTV footage of the hotel from 21 November 2015 showed Mr Lock threatening the night manager and acting erratically.
When police arrived, the teenager ran out of the lobby towards the hotel golf course.
The inquest jury found officers inappropriately classed him as a suspect who was absconding, as apposed to treating him as a vulnerable person.
PC Charlotte Sullivan told the inquest she requested a police helicopter but it could not be provided for "operational reasons".
Shropshire coroner John Ellery questioned why a second call to the National Police Air Service (NPAS) was not made and PC Sullivan replied: "I wouldn't normally ask a second time."
A police dog handler, PC Ian Willes, searched the grounds for 40 minutes and heard a voice shouting "Leonard" - the name of Mr Lock's friend. The police dog picked up a scent, but the teenager was not located.
Two days later, he was found dead in a pond on the grounds by a green-keeper.
The jury at Shropshire Coroner's Court recorded a narrative verdict.
Outside court, Mr Lock's mother Tracey Lock said she was "happy to get justice for Tyrone" who "was a gentleman... and a pleasure".
"I'm so proud to be his mum," she added, but said the family was "broken" without him.
Det Ch Insp Paul Moxley said: "We acknowledge today's verdict and we will now look to work closely with NPAS to review future callout procedures.
"Our thoughts remain with the family and friends of Tyrone following his tragic death."
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