Glasgow residents were left scratching their heads as the skies were shattered by the sound of a huge, low-flying RAF military plane doing loops of the city late last night.
The Airbus A400M aircraft could be heard by locals as it appeared to circle the city, while performing various take-off and landing manoeuvres at Glasgow Airport.
Flight tracking service Flightradar24 showed the plane flew repeated loops above the north and south of the River Clyde before descending to an altitude of at least 600 feet at the airport - and then taking off again.
The huge turboprop military plane was tracked as it flew up to the city from its base at RAF Brize Norton in Oxfordshire, reports Glasgow Live.
It then entering the airspace above Scotland's largest city at around 10.35pm on Tuesday night, before returning south of the border around 35 minutes later at 11.10pm.
Residents took to Twitter to share news of the plane's presence over Glasgow last night, with one tweeting: "Big A400 doing low level flying about Glasgow tonight. Flight from Brize Norton."
Another seemed to have had their sleep disrupted by the flight, writing: "Fuel crisis? Then why have the RAF got planes doing laps round Glasgow at this time", along with a sleep emoji.
A third quizzed: "Anyone got an idea why this RAF flight from Brize Norton is circling Glasgow Airport, dropping down to a few hundred feet, but not landing?", with a fellow Twitter user responding with "Training apparently."
They were joined by a fellow bemused resident who wrote: "RAF plane circling Glasgow, keeps dropping to just above the airport then climbs and does another loop. Weird!"
The RAF Airbus A400M Atlas, which costs in the region of €150 million per unit, operates as a tactical airlifter to deliver supplies or personnel.
An RAF Spokesperson: "A Royal Air Force Atlas A400M aircraft from RAF Brize Norton in Oxfordshire was completing routine and pre-authorised night-flying training around Glasgow yesterday evening.
"The RAF use a variety of locations around the UK for training as they provide complex airspace and differing challenges for our pilots to ensure we remain ready and able to deploy on global operations."
Don't miss the latest news from around Scotland and beyond - Sign up to our daily newsletter here.
