Transport secretary Chris Grayling revealed on Tuesday the government will back expansion at Heathrow, but with another year before the House of Commons actually votes on the matter, the plan is far from having been cleared for take-off.

Much like the aircraft circling Heathrow this afternoon, the challenges in getting the project under way are stacked high: securing ministerial support, legal threats by local residents and pressure groups, and how exactly the UK can expand its air capacity without exceeding its carbon emissions targets, are all obstacles in the flight path.

If and when the expansion finally begins, the question for passengers flying from Heathrow will be – at what cost to them? The government this week insisted that expansion should not be at the expense of travellers themselves, and Heathrow has made the rather bold claim that gaining additional capacity will increase competition, reduce over-demand, and bring air fares down by as much £300 per return ticket.

Even if those calculations are accurate for the short-term, the rate of growth in demand is such that even an expanded Heathrow will soon see its extra capacity filled – so those cheaper fares might not last for long.

Airlines are concerned the costs of the project could be passed onto passengers in the form of increased landing fees – with Willie Walsh insisting the current £40 landing fee on a return flight at Heathrow could be as much as doubled. On top of Air Passenger Duty and the anticipated rise in fuel costs next year, could an increase in landing fees be an increase too far for some clients?

Funding, like every other aspect of the Heathrow project, must be nailed down as quickly as possible, so the expanded network, greater range of carriers and improved domestic connectivity that Heathrow promises can be delivered as quickly as possible. Otherwise it might take the UK another 40 years to catch up.