The incident in March has been classed as a Category A “near miss” - the highest risk level - by the UK Airprox Board, which investigates reports by pilots.
It involved a Ryanair flight arriving from Derry, The Scotsman established, using information provided by tracking service Flightradar24.
The board concluded: “There had been a definite risk of collision.”
Its investigation said the pilot of a Boeing 737, which is used by many passenger airlines, reported passing “100ft above a drone”.
The pilot said: “There was no time to take avoiding action”.
However, despite a police investigation, the drone operator could not be traced after the incident, at 3:50pm on Sunday, 6 March.
The aircraft was descending south west over Glasgow on approach to landing and was at 800ft when the incident happened.
The board’s report said the pilot had assessed the risk of a collision as “low”.
However, it concluded: “The reported separation was 100ft vertically above the drone when sighted, but the Boeing 737 was descending (which would have further reduced the separation as it flew over the drone) and the pilot did not have time to take avoiding action.
“As such, members agreed that there had been a definite risk of collision.”
The report concluded the incident had been caused by the drone being “flown into conflict” with the aircraft.
A Police Scotland spokeswoman said: “A full investigation was conducted, however no arrests have been made at this time.”
A spokeswoman for Ryanair said: “The crew of this flight from Derry on approach to Glasgow Airport observed a large drone operating approximately 100-200ft below the aircraft.
“The crew notified air traffic control and the aircraft landed normally. The incident was reported to police by our crew after landing.”
The Civil Aviation Authority (CAA) said there had been no previous reported near misses between drones and aircraft in Scotland, although several have been recorded over London.
A CAA spokesman said: “It is totally unacceptable to fly drones close to airports, and anyone flouting the rules can face severe penalties including imprisonment.
“Anyone operating a drone must do so responsibly and observe all relevant rules and regulations.
“The CAA’s Dronecode provides advice on how to fly your drone safely and follow the rules at all times.”
The British Airline Pilots Association said tighter regulations on drone use could not come quickly enough.
Spokesman Richard Toomer said: “Unfortunately, the number of near misses between drones and passenger aircraft is increasing as the number of drone hobbyists also goes up.
“We are hoping the UK Government will introduce new safety-first regulations on drones as part of its new bill announced in the Queen’s Speech last week.
“The potential for disaster is real, and everyone must be alive to that risk – pilots, drone users and the government and regulator.”
A spokesman for Glasgow Airport said: “We are aware of the incident involving a drone, which was investigated at the time by Police Scotland. The aircraft landed safely.
“However, we would remind people that operating a drone in such close proximity to an airport is not only extremely dangerous, it is also a criminal act.
“We would urge anyone who witnesses drones being operated in this manner to contact the police immediately.”