Flights can be delayed for myriad reasons these days: Passenger scuffles. Disputes over a birthday cake. The birth of a baby on board. We've heard it all.

But on Tuesday, a China Southern Airlines flight was pushed back after an elderly woman was spotted throwing coins at the plane during the boarding process. One of the coins landed inside the engine, police said.

The 80-year-old woman, identified only by her last name, Qiu, said she had been tossing coins at the plane for good luck, according to Shanghai police.

Police detained the woman while maintenance crew members conducted a "comprehensive inspection" of the aircraft and its engine, China Southern Airlines said in its official account on Weibo, a Chinese microblogging site similar to Twitter.

Local media outlets showed pictures of several investigators peering into an open engine and holding a handful of coins that had been retrieved from the area - including one from within the engine of the Airbus A320.

Police said the woman had no criminal record or history of mental illness, and had tossed the coins at the plane to "pray for a safe flight." Police also said they would not jail the woman because of her age.

Traveller