The aircraft's captain was reportedly forced to intervene and recover the near miss, described as the greatest of its kind in years, while the Airbus A320 descended into Heathrow Airport.
The near miss took place as the jet - flying from Florence in Italy - was at 1,300ft and coming in to land at Heathrow Airport in May when a pilot spotted the small blue drone.
Mohammed Koyes, 58, from Carlisle, Cumbria, knocked back most of a one litre bottle of gin while travelling from Bangladesh to Heathrow Airport, a court heard.
While he was already under investigation for a separate theft, Boudina travelled to Heathrow Airport Terminal 5 where helped himself to passenger's suitcases and rucksacks.