(CNN) It was a crisp winter morning in Sheffield, England, when amateur photographer and plane enthusiast Alan Meloy looked out his kitchen window and noticed a large trail in the sky. He didn't know he was about to accidentally help uncover a highly sensitive, secret presidential trip to a conflict zone.

About six hours before Meloy's discovery, President Donald Trump and first lady Melania Trump were quietly whisked out of the White House under the cover of darkness on Christmas night for a trip to Iraq

"I literally stepped out, and I could see a trail coming towards me and thought let's have a look at what's on the end of that. And then I looked through the viewfinder and thought this is worth photographing, it's not just a normal airliner," Meloy told CNN.

It was that moment that the almost-retired IT project manager, who has been spotting planes for 40 years and enjoys keeping an eye on the skies, knew he was looking at something unique when he saw a distinct color scheme on the plane.

"I was absolutely amazed when that came past...I knew it was one of the two VC-25s," Meloy told CNN. "I had no idea who was on it, in my mind I was thinking it must be someone pretty important."

The VC-25 is a modified Boeing 747-200 used to fly the President of the United States. Only two exist in the world and alternate as "Air Force One."

The plane, which normally flies under the callsign "AF1," had already sparked the interest of online aviation enthusiasts like " CivMilAir ," a popular plane tracking enthusiast based in the UK, when it showed up on the map under the callsign "RCH358" or "Reach 358." "Reach" is used by the military to designate cargo planes. The plane maintained an altitude of about 31,000 feet as it flew across the UK, according to flight logs.

It wasn't until Meloy snapped the picture of the plane that showed "Reach 358" was in fact "Air Force One" flying in disguise, except to the naked eye. He went online to post the picture to his Flickr account and see if anyone else had noticed the aircraft. While some online were intrigued and watching RCH358 others were skeptical, telling Meloy "no it's not Air Force One, it's got a different callsign!" he says.

"So all I said was I know what I've seen, it's a VC-25 there's only two of those in the world -- that's all I can tell you. There's my photograph." Meloy says he didn't want to start any speculation.

The photo picked up steam online and Twitter was soon on fire with speculation that Trump was heading to Afghanistan or Iraq.

A few hours after Meloy spotted the plane through his Canon 7D from around 25 miles away, "Reach 358" secretly landed at Al Asad Airbase just west of Baghdad before the President and first lady met with troops for nearly three hours. Even Trump remarked at the steps of secrecy taken to ensure the safety.

"If you had seen what we had to go through with the darkened plane, with all windows closed, with no lights on whatsoever anywhere. Pitch black. I have never seen anything like it," Trump said while speaking to reporters on base in Iraq. The trip had been in the works for "three to four weeks" Trump said.

Former Secret Service Agent Jonathan Wackrow, who has helped coordinate conflict zone trips for multiple protectees, including a trip of then-President Barack Obama to Afghanistan, says the spotting of Air Force One and Twitter chatter is not a security breach, but is concerning and a lesson to be learned.

"In the age of social media, this highlights a new vulnerability that the Secret Service and military have to be super mindful of in the future," Wackrow says. "You're charting new territory with the inclusion of social media from a threat perspective and from an awareness perspective, and future planning is going to address that."

On Christmas Day, the normal 13-person press pool was assembled quietly and sworn to secrecy -- a long-held tradition and agreement between the White House and Washington bureau chiefs that reporters won't report on secret overseas trips until the White House deems it safe to report, either once the trip is almost complete or the President is wheels up back to the United States.

As the buzz picked up on Twitter and it was becoming more apparent that Trump was heading to the Middle East, the secret embargo was lifted, and reporters struggling to get internet connections were finally allowed to file, confirming many 'avgeeks' suspicions of a secret presidential trip.