Cut-price fares may now be merely a facade for seemingly endless add-on fees after Jetstar’s new carry-on luggage charge meant the airline joined a growing number monetising basic services in the sky.

The new structure, announced by Qantas’s low-cost carrier on Wednesday, will mean from next year tickets will only include one “under seat bag”, such as a backpack, handbag or laptop bag.

Customers with stowed carry-on luggage will face an additional layer of fees, building on costs for check-in baggage, preferred seats, cancellation rights and meals and snacks.

It is the latest pricing change in a sector where multiple airlines now even give passengers an option to pay to be next to a vacant seat, in a clever strategy that allows carriers to charge for tickets that do not otherwise sell.

In an extreme example of pricing changes, Canadian airline WestJet reconfigured its aircraft last year, requiring passengers to pay an extra fee if they wanted a seat that reclines.

Such changes are usually marketed by the airlines as a simplified, user-pay system that keeps entry level prices low for those looking for a cheap fare.

But Graeme Hughes, a consumer expert and adjunct associate professor at Griffith University, says it further obscures the checkout price.

“This allows Jetstar to broadcast the cheapest price, but of course those add-on costs are something which are going to hit you as you click through the booking process,” Hughes says.

“There will be frustration there for travellers because it means they can’t easily do an apple-for-apple comparison with other airfares.”

Andy Kelly, the campaigns director at the consumer advocacy group Choice, says Jetstar’s new policy is “just an easy cash grab, really”.

“Already, to choose seats could be over $20, around $50 if you want the ability to cancel your flight to get a credit, and then an additional $50 to join their loyalty program to get a discount,” he says.

“They just make it really hard for consumers to make an assessment of value and also to compare different products.”

European experience

The EU recently mandated that airlines – along with booking platforms and search engines – will have to display air fares that are inclusive of carry-on luggage at the outset of the booking process, to make it easier for consumers to compare prices.

The European Council introduced the mandate after fierce pushback from the airlines to an earlier proposal by the European parliament to give passengers the right to carry on a small case for free, as well as the free under seat bags currently permitted.

In its press release, Jetstar said its shift to a “size-based carry-on baggage model” was similar to other low-fare carriers around the world.

Jetstar also claimed the model helps keep fares low because “you only pay for what you need”.

Jetstar has tried to present the change as a positive development for travellers, but it is also following the lead of these overseas carriers in charging people to bring anything other than a small bag or item that can fit under the seat in front of them.

Dr Ian Douglas, an honorary senior lecturer at the University of New South Wales’ School of Aviation, says pretty much every low-cost carrier in Europe charges some sort of fee, including Ryanair and EasyJet.

“It’s a little sad we’ve gone straight to the Ryanair model because Jetstar is not Ryanair,” he says. “Jetstar is filling a gap in the Qantas network.

“If you want to go to the Sunshine Coast or Cairns [for example], it’s quite likely the offer will be Jetstar and not Qantas.”

Jetstar says the new fee will depend on the length of the flight and has acknowledged that fees may change. It can exceed $100 to carry an overhead bag on an overseas trip, according to Guardian Australia analysis of different Jetstar routes.

Ireland-headquartered Ryanair charges passengers €/£12-€/£36 if they pay when booking, or €/£20-€/£60 if they pay at the airport.

Britain’s EasyJet says its fees vary, including based on demand. Passengers who don’t pay in advance are charged £60 at the boarding gate.

The German low-cost carrier Eurowings charges basic-fare customers fees from €18 or £16 for “large” carry-on luggage.

In the US, leading low-cost carriers JetBlue and Southwest include a small personal item and a larger carry-on bag in their fares, while Frontier charges passengers based on their route.