Britain's bottlenecked skies
Air routes come and go, depending on whether they can justify the airline's costs. For an outfit like Turkish, it'll probably take a few years to get a return on its investment on the flight, inaugurated on Monday, linking Edinburgh with Istanbul.
This isn't just another sunshine destination. It's a link with a country and an airport that increasingly views itself as a hub for the Middle East. Istanbul is a rival to Dubai as a connection point between the west and fast-rising Asia.
Getting such air links are important to Scotland. The Emirates route between Glasgow and Dubai has recently increased capacity with twice-daily take-offs, and with a first class cabin now on offer.
That success story is a credit to the Air Route Development Fund, which was set up in the early years of devolution, but forced out of business by European state aid rules, without any replacement yet found.
Even critics of aviation can give a subdued one cheer to such direct links, because point-to-point air routes in more efficient aircraft use less fuel per passenger and do less environmental damage than multiple take-offs and landings required by connecting flights.
Not cleared for take-off
But direct flights are no substitute for sorting out the problems of Heathrow. It's operating at more than 99% runway capacity. The border control queues may be long for the Olympics in the next few weeks, but it's the longer-term problem of fitting in all those landings and take-offs that is becoming more of a political and economic issue.
So far, it's grabbed attention at Westminster that the coalition can't agree on what to do about airports in south-east England. A consultation was expected last week, but Transport Secretary Justine Greening ducked the issue of Heathrow, and talked vaguely about less pressing issues; for instance, a western rail route into the west London hub, and encouraging direct flights for English regions.
If a consultation is ever launched, the key question is whether it includes the option of allowing a third runway at Heathrow. That was ruled out when the coalition took office, but it could be brought back into play, as merely another U-turn.
Or there could be a new hub airport on the Thames Estuary, either on reclaimed land or by building up Southend. That's far from easy and doesn't connect up, any more than using spare capacity at Stansted, to the north of London.
Unlike much else, the politics is not just another Tory-Lib Dem split. It's more complex than that, within the two parties. There are concerns about the environment and meeting emissions targets, plus noise pollution affecting marginal constituencies in west London.
But there are also concerns that constraining Heathrow's growth is to constrain the UK economy's growth. The business lobby in London and elsewhere is making that point loudly, with Heathrow's owner, BAA, keen to help.
Part of that economic story, though hardly a prominent one so far, is the impact on the other parts of the UK that depend on good links into Heathrow.
They are fewer in number than they were. Because of faster rail links, England's northern cities have fewer scheduled air connections with London than they used to have.
(Transport enthusiasts may wish to note that the announcement on rail in England and Wales on Monday includes improvements to capacity and punctuality on the East Coast line as far north as Newcastle, and that ought to improve services to Edinburgh as well.)
With less pressure from English cities, the London logjam matters to the parts of the UK further flung from the capital - Scotland and, even more, Northern Ireland. The governments at Holyrood and Stormont aren't too worried whether their voters can jet to the sun on Ryanair, Jet2 or Thomas Cook.
What concerns them (or it ought to, anyway) is that inbound international tourists can land at Heathrow and transfer easily and reasonably cheaply to domestic UK flights. Even more valuable is the business cargo, ensuring that Scottish and Irish-based business-people can get to markets, and that inward investors can get to Scotland and Northern Ireland.
And for those (including British Airways boss Willie Walsh) who say there are already plenty links to other London airports, they're missing the point that high-value passengers often can't be bothered changing terminals, let alone getting from Heathrow round the metropolis to Stansted or Gatwick.
The problem is that, while Heathrow landing slots are scarce and cost a lot, with British Airways dominating them, the best way of extracting value is to use them for large planes flying long distances. Smaller planes linking to destinations within the UK, or to smaller cities in Europe, get squeezed out by the financial logic.
That way, Heathrow loses feeder traffic. The high costs, relative to European rivals at Paris, Amsterdam and Frankfurt, also makes them more attractive to airlines based in emerging economies that are looking to open up new routes.
Aviation experts note that links to some Chinese cities are looking to Europe's continental destinations, rather than bringing business into bottlenecked Britain.
They're also contrasting the high costs of Air Passenger Duty (for instance, £260 for a family of four heading for the USA) with much lower departure tax take by Britain's rivals.
One partial solution to this capacity constraint is that British Airways has been forced by the European competition regulator to sell some slots it gained when it bought BMI earlier this year. That removed rivalry over Heathrow traffic to Edinburgh and Aberdeen.
Glasgow's had already been axed by BMI last year. And Inverness has no link to Heathrow at all, when transfers of Highland-bound tourists could make a significant difference to the tourism industry, starting with Castle Stewart golf course, right next to Dalcross Airport. According to figures out on Monday, Inverness's passenger numbers are rising on the success of its KLM link to Amsterdam's Schipol.
With British Airways monopolising the bigger city routes, prices are being watched carefully by Scotland's tourism chiefs for signs of upward drift.
We don't yet know who will buy those slots being freed up, and how well they'll operate them to Scotland and Northern Ireland. But we can be confident that it matters.