THERE has been a huge increase in the number of passengers flying between Scotland and America in the past year as more direct transatlantic services are introduced.
Traveller numbers soared by more than a quarter during 2006 - and aviation experts are expecting a further rise this year as even more flights are added to busy schedules.
Figures from airport operator BAA Scotland reveal that 561,331 passengers flew between the US and Glasgow and Edinburgh airports last year, up 28 per cent from 436,849 in 2005.
At the peak of last summer there were 49 flights a week to the US, departing from the two key Scottish airports.
This summer, that will increase to 53 flights a week, with four airlines operating flights - mostly daily, with some twice daily - to New York, Atlanta, Philadelphia, Orlando and Boston.
With such strong competition for passengers between Continental, Delta, US Airways and FlyGlobespan, it is perhaps no surprise that there has been a casualty - even before the start of the summer timetables.
American Airlines has axed its daily summer-only service from Glasgow to Chicago, blaming poor demand and saying it struggled to attract lucrative business class passengers because of the lack of year-round flights.
That decision has led some commentators to claim there are now too many airlines operating on the routes. But BAA Scotland argues the transatlantic market is not over-saturated and is continuing to work to add more new destinations.
The carrier with most flights from Scotland to the US this summer will be Continental. To meet booming demand the airline is boosting its summer schedule to 25 flights a week to Newark in New Jersey flying a twice-daily service from Edinburgh and 11 services a week from Glasgow.
This represents a massive 78 per cent rise on the regular capacity the airline offers in the winter period, when it operates a lower frequency of 14 flights - one a day from each airport. Continental first flew daily from Glasgow in 1998, adding services from Edinburgh in 2004.
Company spokesman Bob Schumacher says: "We are delighted with the success of our Scottish services, and we continue to try and match supply with demand.
"Strong economies on both sides of the Atlantic aid this position for both business and leisure traffic. The additional services will make it more convenient than ever for Scottish travellers to access the whole of America. We offer onward connections to 230 cities via our Newark hub."
Continental says the Scottish business community "underpins the success of the route" in what is a highly competitive sector. Schumacher adds: "Corporate Scotland has been loyal to both the Glasgow and Edinburgh services, allowing them to travel direct to New York and beyond without the delay and hassle of transferring over larger airports like Heathrow."
Delta will celebrate the first anniversary of its daily year-round flight from Edinburgh to Atlanta in June.
Although Atlanta may not immediately spring to mind as a top destination in America, the main attraction of the new service is that it flies to the largest airline hub in the world.
In the first nine months of operation, more than 64,000 passengers have used the service. Armin Venencie, Delta's sales director for the UK says: "As we head towards the one-year anniversary of this flight, we are experiencing strong year-on-year bookings growth.
"This highlights the popularity of this route and how much Delta has become a core part of Scotland's aviation industry.
"In addition to travelling to Atlanta, many passengers are also connecting onwards to other destinations throughout the US and the Caribbean."
Top destinations for Delta's Scottish passengers include San Francisco, Washington and Las Vegas. Just before Delta launched its service last summer, Continental unleashed a vicious attack on its rival, predicting the Edinburgh to Atlanta link would be "gone within 18 months".
Nearly a year later, Continental says it still remains sceptical about the demand for such a service. Schumacher says: "American Airlines' decision to scrap its Glasgow to Chicago service shows how difficult it can be to sustain wide-bodied transatlantic services between Scotland and secondary US markets.
"We don't know the performance data for Delta's service, but we know it has had no adverse impact on our own Edinburgh operations.
"We believe that by using the Boeing 757 we have the right product for the Scottish market. We are also flying to the right destination - New York."
Delta refused to get involved in a war of words with Continental, but Venencie responds: "Our success on this route shows we have made the right decision. We never enter a market if we don't think we will last and we will be in Edinburgh for the long term." Expanding Scottish airline FlyGlobespan certainly believes there is room for further expansion, and launches a new daily service linking Glasgow with Boston in May.
The new service means FlyGlobespan will be operating two routes daily to America over the summer as its Glasgow to Orlando service - launched last June - increases frequency from three flights a week during the winter, back up to seven from May.
The new summer schedule signals founder Tom Dalrymple's intention to transform the airline into "Scotland's national carrier."
Dalrymple says choosing Boston as the airline's second US route from Glasgow was an easy decision. "Boston is a very exciting destination. The city itself is very popular with tourists and it is also the gateway to New England," he says.
"There are strong business and cultural links between Massachusetts and Scotland, and we expect the new flight will be well received by the business community on both sides of the Atlantic - as our prices in this sector compare very favourably with others."
A spokesman for BAA Scotland says: "The US market remains one of the strongest and most important tourist markets for Scotland, with more than half a million crossing the Atlantic, making 2006 a record year for transatlantic travel.
"Scotland and the United States enjoy historic ties, and we see these ties as a key driver for the leisure market. There's no doubt that Scottish business also benefits as a result of Scotland's growing network of direct services.
"With FlyGlobespan operating daily to Boston, Continental increasing frequency to New York, Delta enjoying healthy growth, and US Airways making a welcome return this summer, the prospects for the US market look good."
But in light of the decision by American Airlines to pull out, airport officials have issued a stark "use them or lose them" warning. The spokesman adds: "Too many flyers still go via London because they have airline loyalty cards or are maximising their air miles. It is clear the business community could do more. It is still not using all the direct flights we have."