Not all airlines are offering automatic Air Passenger Duty refunds despite abolition of the tax for children aged under 12 from May 1, according to new research.

The travel industry is “awash with various rulings” as to how eligible consumers can reclaim the tax if they are flying with children this summer, financial comparison website claimed.

Some airlines such as British Airways, Thomson, Virgin Atlantic and American Airlines are offering automatic refunds to passengers who booked flights for under 12s that take off  after the May 1.

Ryanair implemented the APD changes for under-12s from the March 27 – almost six weeks early. EasyJet is also taking a proactive approach in contacting customers by calling or emailing to ensure they know how to reclaim their money.

However, many carriers are asking consumers to proactively apply for a refund.

“With airlines already struggling to deal with applications for compensation for delays, this could add to the administrative backlog,” warned.

Research among 1,000 parents with children aged 2-11 who fly revealed that one in three parents would not apply for an APD refund regardless of the amount.

In addition, just 37% would apply for a refund of £13 or less, which is the amount parents would receive on short haul flight.

“This could lead to a pot of unclaimed money being left in ‘APD limbo’,” the company said.

More than half of parents (58%) with children aged 2-11 think the airlines should automatically refund APD charged on flights from May 1 if they are booked before this date.

More than a quarter (26%) feel airlines that are making consumers apply for a refund should proactively contact them and provide full details as to how they can apply.

One in three (32%) feel they should be informed about the refund process at the time of booking, the study found

Hannah Maundrell, editor in chief at said: “Overall, it seems that many of the airlines are doing the right thing and issuing automatic APD refunds to parents that are booking flights for the under 12’s.

“However, others are operating a refund by request system and this could be one extra job that many parents never get around to doing, leaving much of the money stuck in APD limbo.

“Airlines are already awash with consumers trying to reclaim money for delays, these new applications for APD refunds could simply add to the administrative nightmare.

“We fully appreciate the complexity of implementing the government’s changes in less than six months. However, with little consistency in the way airlines are dealing with these refunds, some consumers could end up missing out on money they’re owed.

“The important point here is that anyone that’s booked a flight for a child aged 2-11 for after May 1 must check whether they paid APD. If they did, they need to make sure they get the money back from either the airline or the travel agent.

The British Air Transport Association told the Mail on Sunday that a standardised approach had not been possible due to the short time-frame between the announcement of the APD changes in the Chancellor’s autumn statement in December and its implementation and that not all airlines have details of passengers ages.

APD for children under the age of 16 flying in economy class will be dropped from March next year.