Helen Liddell is a typical politician. Lots of vote-winning posturing about increasing flights, but no idea at all of the economics. The Sunday Times is at least a little less naive.
Airlines have, for years, been exploring the possibilities for new routes. Airports are constantly trying to identify viable routes, and sell them to the airlines. The truth is that only a handful of routes ARE in fact viable. Even the domestic scottish routes would not survive without subsidy (ie routes inside scotland). Have a look at the number who have tried, failed and are now just distant memories. Others manage to struggle from financial crisis to financial crisis with little hope of ever being properly profitable. Others struggle just to start (don't they Guv!)
Airlines are in the supply-demand business. Demand for transatlantic travel is already more or less satisfied, in volume if not in choice. Certainly with the current seat mix and yield plans.
Maybe if Ms Liddell was to stimulate tourism in Scotland, thus providing demand, the airlines would react with more routes. Until then, forget it. Airlines need to make money, not lose it on fanciful political idealism.