The Scottish government had hoped to replace the tax with a new devolved Air Departure Tax (ADT) in the country from April next year which they hoped would be half the current rate before ultimately being abolished.

However, the BBC has reported it said that to continue exempting journeys from airports in the Highlands and Islands required EU approval under state aid rules.

Gaining the approval could take longer than Brexit, leaving the Scottish government with a bill of £320 million to maintain the exemption in the meantime.

Opposition parties have said MSP finance secretary Derek Mackay is preparing to U-turn over cutting the tax, a charge that he has denied.

Now the SPAA has weighed in with president Alan Glen saying: "Our members had expected Air Passenger Duty on flights out of Scotland to be halved by next April.

"The promised APD reduction was not only meant to be a boost to the general Scottish economy by attracting more inbound visitors, but also to the outbound travel trade - by making more direct airline routes from Scotland feasible and by making travel more affordable.

"This proposed reduction in APD wasn’t just something that would have benefited a few wealthy business travellers, but on the contrary would have meant more money in the pockets of everyone who travels for business or for pleasure.

"The exemption for the Highlands and Islands has been in place for many years.

“It is not a surprise and I am assured that the European Commission would be most unlikely to suddenly change its mind and object after all this time.

"This looks like an excuse rather than a reason. The travelling public deserves proper transparency from Scottish ministers on why this long-standing promise has been put off again."

A Scottish government spokesman said: “We have set a clear aim to reduce Air Departure Tax by 50% and abolish it altogether when resources permit.

“However, we want to protect the existing Highlands and Islands exemption, which needs approval by the European Commission – and that requires action by the UK Government, as the relevant member state.”