As passengers we see only a tiny part of airports, which are probably full of intriguing stories if you know where to look.
However at one Spanish airport, a hulking aviation oddity has been hiding in plain sight.
Officials from the Adolfo Suárez-Madrid Barajas airport are trying to find the owners of a plane that has been parked on the tarmac, without moving, for years.
Airport director Elena Mayoral submitted an official notice to the Boletín Oficial del Estado, the official gazette of the Kingdom of Spain, informing the nation of a plane in an “obvious state of abandonment” at the airport.
The plane is a McDonnell Douglas MD87, according to the notice, registration number EC KRV.
A similar plane, converted to a luxurious private jet, is currently on sale for $4.8 million at Bloomer deVere Dahlfors, a jet sales company in California.
It has not been confirmed how long the plane has been parked.
A spokesperson for Madrid Barajas airport told CNN via telephone that the plane is the only aircraft currently abandoned at the site.
Under Spanish law, authorities must publish official notices about the plane for three consecutive months and then wait a year to see if the owner comes forward to claim it.
If they do not, the plane will be considered legally abandoned and will be sold off by the state at a public auction.
While many planes lay idle at graveyards around the world, it is relatively rare for them to be abandoned at working airports.
Another similar case occurred at Kuala Lumpur International Airport (KLIA) in Malaysia in 2015.
Three huge Boeing 747 cargo planes were abandoned at different times at the airport, prompting an appeal to find the owners after the jets were left untouched for over a year.
Airport officials, eager to clear the massive clutter, took out ads in Malaysia’s The Star and Sin Chew Daily newspapers asking for the owner to kindly come and collect their planes.
In December, CNN observed two of the three abandoned planes still sitting at the airport.
However, these two cases are unusual in an industry that usually has the infrastructure in place to handle unwanted aircraft.
Spain is home to the largest industrial airport in Europe, at Teruel in the east of the country.
It hosts aircraft from all over the world that have been withdrawn from service, be it temporarily or permanently, and caters to their maintenance needs.
Some aging airliners may be scrapped here (after being stripped for valuable parts and spares) but plenty of new, perfectly serviceable aircraft are also stored in Teruel.
A few of them are ready to fly but are waiting for financial or legal issues to be sorted out. Others are there because their airlines need to temporarily adjust capacity to cope with fluctuating market conditions.
This story has been corrected to reflect the status of the abandoned planes at KLIA airport.
CNN’s Brad Lendon contributed to this report.