An Angklung (Malay musical instrument), X-ray films, hearing aids, dentures, surfboards and even a washing machine - these are some of the stranger items which increasingly forgetful travellers are leaving behind at Changi Airport.

Sats - the airport's biggest ground-handling agent which deals with Singapore Airlines and other carriers' flights - recovered around 17,000 items left on planes last year.

This is more than 11/2 times the 11,000 items found a year ago.

Changi Airport Group, which maintains a separate list of things found at the terminals, recovered 7,680 credit/ATM cards and mobile phones last year compared with 7,180 in 2013.

The cards are kept for three days, after which they are cut up.

The number of lost and found items has gone up despite growth of just 0.7 per cent in overall passenger numbers at the airport between 2013 and last year.

Apart from phones and cards, sweaters, jackets, shawls, books and tablet devices are the other more common items people leave behind.

But more unusual items, including hearing aids, breast pumps, a bird cage and cabinet doors, have also turned up.

The items are either handed over to the airlines or kept in the lost and found offices, a Sats spokesman said.

Where possible, the owners are tracked. For instance, if something is found in the seat pocket, it likely belonged to the passenger who was sitting there and attempts to reach the person will be made, she explained.

She highlighted how a mobile phone was eventually delivered to its rightful owner in his Singapore office after he left it on a plane from Los Angeles.

When items are found on foreign aircraft, these are sometimes returned to the airline's head office after about a week, Sats said.

All other unclaimed items are typically kept for about two to three months and then donated to charities such as the Salvation Army.

Sats' senior vice-president (apron and security services) Denis Marie said: "On average, we logged about 46 cases of lost items per day last year....

"We understand the anxiety that passengers experience when they lose something important or valuable and would advise that they check under their seats, seat pockets and the overhead compartments thoroughly before disembarking."

karam@sph.com.sg