In 2018, airlines generated an estimated total of about 6.1m tonnes of cabin waste, of which between 20% and 30% was untouched food and drink.

This is according to research by the International Air Transport Association (Iata).

"Cabin waste is a significant issue for airlines, but it is not solely in airlines' power to resolve. This is because regulatory restrictions inhibit re-use and recycling," Michael Gill, director of the aviation environment at Iata, said at the industry body's 75th annual general meeting in Seoul, South Korea, on Sunday.

At the Sustainable Cabin Forum in May airlines and regulators met to discuss how they can collaborate to address the issue of cabin waste.

"The aim is to promote technical solutions that support the circular economy and reduce industry costs. With better regulation we can reduce waste," said Gill. "Airlines cannot solve the issue of cabin waste on their own. Regulations are very strict in this area. We are undertaking research to understand the problem."

Research by Iata at London's Heathrow airport in 2012 and 2013 indicated that a typical passenger generates about 1.45kg of cabin waste. This was the average found across both short and long-haul international flights.

Food, drink and recyclables

About 23% of this cabin waste per passenger was untouched food and drink and a further 17% was recyclable materials like plastic bottles and newspapers.

Gill pointed out that all cabin waste is subject to national waste management controls that limit pollution. Many countries have, however, gone further with their regulations by introducing restrictions on catering waste from international flights.

According to Gill, these regulations often lead to the incineration of all cabin waste and a limited ability to re-use and recycle.

The World Economic Forum (WEF) expects plastic production to double in the next 20 years. At the same time, plastic recycling rates remain low, especially in developing countries.

Regulations placing restrictions on so-called single use plastic (SUP) - like water bottles - have increased significantly and impacts the aviation sector, according to Gill.

"Although airlines are supportive of reducing (plastic) litter, the selection of alternative solutions should consider not only its environmental characteristics, but issues of availability, affordability, hygiene, food safety and the weight and space it takes on board," explained Gill.

Iata has, therefore, developed cabin waste recycling guidelines for international flights. The aim is to ensure airlines are able to meet the requirements of the various regulatory regimes globally; that the regulations are flexible enough to accommodate a wide variety of airline operating models; and that they incorporate best waste management practices from within the aviation industry.

According to Gill, the environmental impacts to take into consideration include increased energy and water consumption from cleaning and return logistics; water pollution from washing; as well as carbon emissions that result from heavier materials carried on board aircraft.