Norwegian is to axe a US route from Edinburgh and cut back its two others because of ministers postponing a reduction in air taxes.
Norwegian will end flights to Bradley in Connecticut in March, just nine months after they were launched.
Its route between the capital and Stewart, north of New York City, will be reduced at the same time from daily to four a week.
Flights to Providence in Rhode Island, south of Boston, will be trimmed from five times a week to three.
An industry source described the routes' "load factors" - proportion of seats filled - as "poor".
Between June and November it was 58 per cent for Providence, 66 per cent to Bradley and 71 per cent to Connecticut.
Edinburgh Airport said it was the first time an airline had curtailed flights because of the tax delay.
The Scottish Government had intended to halve air departure tax, its new version of air passenger duty, in April.
However, the minority administration faced opposition from all the other parties at Holyrood to its proposal.
Then finance secretary Derek Mackay announced in October the plans were on hold because of the need to get EU approval to continue exemption from the tax for airports in the Highlands and Islands.
A Norwegian spokesperson said: “Following our launch of affordable transatlantic routes from Edinburgh last year, the prospect of a reduction in air passenger taxes meant we had been planning for continued future growth in Scotland.
“The Scottish Government’s postponement of a reduction to air passenger taxes was therefore deeply disappointing and has led us to review existing transatlantic services from Edinburgh, with the decision to cut the route to Connecticut and to reduce the frequency of flights to the Boston and New York areas.
"We will be reallocating this capacity into other markets where air passenger taxes do not present a barrier to our growth."
The airline added: “We still see huge potential at Edinburgh, and due to passenger demand we will be maintaining seven flights every week.
"However, we urge the Scottish Government to quickly resurrect plans for a reduction in air passenger taxes which would re-open the door to more flights and lower fares for passengers and a boost to Scotland’s connectivity.”
A spokesman for Edinburgh Airport said: “This is deeply disappointing for both Edinburgh and Scotland.
"The Scottish Government’s commitment to cut aviation tax has factored in a number of airlines’ investment decisions as it allows us to compete with other countries.
“What we see here are politicians actively costing Scotland connectivity and harming the economy.
"We’ve lost a plane, a route and jobs.
“Importantly, we’ve also signalled to airlines that Scotland is perhaps not as attractive as it seems.
“The Scottish Government must double its efforts to resolve the issues surrounding Air Departure Tax and fulfil its promise to airlines and Scottish passengers.”
A Scottish Government spokesperson said: “We have set out a clear aim to reduce the burden of air passenger taxation by 50 per cent by the end of this parliamentary term, and abolish it entirely when public finances allow.
“We will continue to work in partnership with Norwegian and other airlines, and with all Scotland’s airports, to grow the number of international routes to and from Scotland.
"To protect the economy and connectivity of the Highlands and Islands, the introduction of air departure tax in Scotland has been deferred until the issues raised in relation to the exemption for flights departing from the Highlands and Islands have been resolved.
"The Scottish Government and UK Government will work closely in order to achieve this as early as possible.
"The UK Government will maintain the application of air passenger duty in Scotland in the interim."