There's been a big focus on the carbon footprint of flying — but have you ever wondered how much rubbish you generate as a passenger on a plane?

Key points: The average person creates 1.4 kilograms of waste per flight

The average person creates 1.4 kilograms of waste per flight In 2017 there was 5.7 million tonnes of passenger waste

In 2017 there was 5.7 million tonnes of passenger waste Low cost of plastic makes it the go-to for packaging on board aircraft

The question was on my mind as I headed off on a recent holiday, so I decided to conduct an experiment.

I collected all of the single-use plastics that found their way onto my tray table, before the hostess could whisk them away.

After a 10-hour return trip, I'd gathered a hefty bag of plastic cups, cutlery, water bottles and food packaging — and that was just my waste.

The average passenger generates 1.4 kilograms of waste per flight, according to the International Air Transport Association (IATA).

In 2017, the total amount of passenger waste was 5.7 million tonnes, IATA says. This figure includes toilet waste, but the bulk of it is paper, cardboard and plastic.

And with more people flying, that amount is only set to go up, unless something changes.

Where does all the rubbish go?

Chris Goater, a spokesman for the IATA, says due to strict quarantine regulations, passenger waste is mainly incinerated or taken to landfill.

"For flights landing in Australia, New Zealand, Europe and the United States, waste is often incinerated because of the risk of transmission of animal diseases," Mr Goater said.

"As much as we'd like to reuse or recycle, regulations don't allow for that."

Mr Goater says more recycling occurs on domestic flights, which don't have to adhere to such strict regulations.

However, these flights are often shorter and generate less waste.

In countries with strict biosecurity laws, anything that poses a contamination risk is destroyed. ( ABC RN: Fiona Pepper )

Dr Susanne Becken, a professor of sustainable tourism at Griffith University, says waste disposal varies wildly depending on the airline and the flight's destination.

"It really depends on how genuine the airline is to reducing waste and then whether there are systems on the ground," she said.

"[But] the default option is everything gets destroyed, and that's of course ridiculous."

According to Dr Becken, Australian and New Zealand airlines are considered some of the more environmentally progressive.

However, she says these countries also have the strictest biosecurity laws.

"Essentially when you have anything on board in particular Australia and New Zealand where we are so concerned about biosecurity, it has to be destroyed," she said.

"Literally everything — even a can of coke that has not been opened."

Why the need for plastic in the air?

Dr Becken cites the relatively low cost of plastic as one of the main reasons it has become the go-to for packaging on board planes.

"It's still pretty cheap — too cheap because we don't account for the external costs and impacts it creates," she said.

"And there are regulations around hygiene, things have to be packaged to some extent and alternative packaging is more costly at this point."

The other factor is the light weight nature of plastic — and less weight makes a plane more fuel efficient.

"Plastics are lighter than metal or porcelain, it's an easy solution," Dr Becken said.

Mr Goater says finding alternatives to single use plastic is more difficult than some may imagine.

"Replacement is not straight forward, metal is not allowed for safety reasons, ceramic increases weight and therefore co2 emissions," he said.

Are airlines taking their waste seriously?

While Dr Becken believes the majority of airlines aren't addressing the issue, she says a few, such as Qantas and Air New Zealand, are environmentally engaged.

"People are becoming sensitised to the use of plastics, and for some airlines that has become a major issue in terms of customer complaints," she said.

Single-use plastics on board planes is becoming a major source of customer complaints. ( ABC RN: Fiona Pepper )

She says Air New Zealand's single largest customer complaint involves concerns about the use of throw-away coffee cups.

The airline has now made a commitment to recycle its single-use plastic cups.

Qantas, meanwhile, has introduced plastic-free headsets and pyjamas, a move it says will "divert one metre of plastic per person from landfill on every flight".

On the domestic front, Qantas also donates leftover catering from domestic flights to the food rescue organisation OzHarvest.

Aside from managing customer concerns, the cost of waste disposal provides an incentive for airlines to reduce cabin waste.

IATA estimates disposal costs for airlines add up to $700 million per year.

"We could get a little more momentum for change if people realise the environmental cost and the financial cost," Mr Goater said.

What's the solution?

Dr Becken believes there are many effective ways to reduce waste on board a plane.

"There's a lot of clever ways of minimising plastic, they take a little bit of innovation but again it's the airlines that are committed that come up with solutions," she said.

It could be as simple as re-using the one plastic cup throughout a flight, or looking at alternative light-weight packaging using biodegradable materials.

Dr Becken also suggests pre-ordered meals —something many low-cost airlines already do.

"There's a lot of items that end up on your plate by default that you literally don't want," she said.

What about waste regulation?

Mr Goater is adamant that new waste regulations are the only real solution to the problem.

"We need to change international catering regulations," he said.

Quarantine regulations are an important issue of public health, but he says the IATA is currently doing trials to demonstrate where regulations could be relaxed.

"We need a more common-sense approach because there are examples where we don't have to be quite so draconian with the issue," he said.

However, Dr Becken is slightly more sceptical at the suggestion of introducing airline waste regulations.

"Most countries don't even have regulation for on-the-ground waste and certainly the airline environment is more complex, which makes regulation extremely difficult," she said.

"Anything to do with the airline industry, because of its international nature and complexity, usually mean it is very hard to implement."

But she does have one suggestion to create change: "I think the better way is to appeal to the company. If there's not feedback there will be no change."