Northern Ireland's airports could be losing out on 11 direct routes to locations from Morocco to Munich because of air passenger duty (APD), a report has found.
Trade body Airlines UK argues that routes such as Belfast International to Dusseldorf in Germany, Lisbon in Portugal, Rome and Marrakech in Morocco would be viable were APD to be abolished.
And it maintains that the same routes would also be viable from George Belfast City Airport if APD - which is payable on short haul flights out of Northern Ireland - was removed.
The research commissioned by Airlines UK identified 66 potential new connections across the UK that could be more viable if the tax was abolished.
The study, carried out by consultancy Frontier Economics, also found that several routes dropped by airlines for financial reasons in recent years could have been viable if APD had been abolished.
Airlines UK said that "APD at £13 for each leg of a journey can account for as much as half the price of an off-peak short-haul ticket (from the UK to Poland) and 44% of the price of an off-peak long-haul ticket (from the UK to Israel)".
The rate of APD from the UK for long-haul passengers is £78 in economy and £156 in premium seats, with short-haul trips charged at £13 in economy and £26 in premium.
However, Northern Ireland has abolished APD on long-haul flights although campaigners in the industry have been calling for all forms of APD to be cut.
Belfast International boss Graham Keddie has said that if APD was scrapped, airlines were queuing up to add the equivalent of a million seats each year.
Airlines UK chief executive Tim Alderslade urged the Government to "get rid of this damaging tax".
He said levying the "world's highest rate of tax on air travel" is incompatible with creating the right conditions for post-Brexit economic success.
He added: "APD is putting the brake on the UK's economic growth with dozens of potential services - including long-haul connections outside of London - unviable under current conditions.
"The removal of APD will leave airlines in a position to respond with more routes, greater frequency and better connectivity for the whole of the UK."
DUP Strangford MP Jim Shannon said: "This is yet more compelling evidence that the current high level of UK APD is damaging the overall UK economy.
"We're particularly hard hit in Northern Ireland as we share a land border with a country with no equivalent aviation tax.
"Every extra route means more quality jobs and increased growth.
"Northern Ireland needs action on this tax, and so does the rest of the UK; action to boost jobs and trade. My colleagues and I will be pushing hard for this in the upcoming budget."
Chancellor Philip Hammond launched a consultation on abolishing APD and introducing a lower rate of VAT for the province's tourism industry in March.
EasyJet chief executive Johan Lundgren said that removing APD would allow airlines to provide "more routes and lower fares", while Virgin Atlantic boss Craig Kreeger called on the Government to show it is "serious about helping us to connect to international markets".