Expansion vs. environment: a false dichotomy

By definition, airports connect people, business, goods and freight – and their unique reach means that as they grow, the economy grows. But friction between business growth and environmental responsibility has been the subject of heated debate for some time, particularly in the UK, historically leading to restrictions on airport operations and expansion.

When airports are not permitted to expand, unrelenting demand creates increasing pressure to operate at the edges of capacity, within the confines of existing infrastructure, often testing the airport’s resilience to its limit.

In fact, restrictions on expansion can stifle environmental opportunities and create a more negative impact than if expansion had been permitted. For example, having fewer runways limits approach and departure routes and can mean air noise impacts increase for local residents. Whereas extra airport capacity creates the option to alternate the runways, creating predictable periods of respite for local communities whilst enabling more frequent flights.

Economic growth generated by airport expansion does not have to come at the cost of the environment. In fact, when done right, responsible expansion can actually enable opportunities for positive environmental progress, catalysing the changes needed for increased sustainability.

The key is to balance development plans with environmental priorities, and there are several key design considerations that can reduce the environmental impact of expansion.

Airside innovations

 The design of airframes and new manufacturing technologies are contributing to the ongoing evolution and increasing efficiency of aircraft. If we look back 20 years, wide-bodied planes with four engines which were noisy, heavy and relatively inefficient, were prevalent.

These planes have been replaced by new models like the Airbus A350 and Boeing 787. New variants such as the Airbus A321 XLR, a single-aisle two engine aircraft is over 30% more efficient than the aircraft it is replacing in the Boeing 767/757 category.

When we consider the emissions of aircraft on the ground, it’s clear that airfield design has huge potential to reduce the carbon footprint. Efficient airfield design ensures that an approaching aircraft can land, vacate the runway, get to its parking stand and turn its engines off as soon as possible; and vice versa. Current limitations on airfield capacity mean aircraft are routinely held on the ground, and more significantly in the sky often for 30-40 minutes, negating any efficiency gained during the flight.

Airspace design also needs to be modernised to reduce the emissions and noise footprint of airports. Existing airspace for commercial aircraft was designed several decades ago and the current system doesn’t lend itself particularly well to the satellite navigation and technologies used by modern aircraft.

There’s significant potential to eliminate unnecessary emissions from indirect routings and use of intelligent navigation to reduce noise in sensitive communities. And of course there are advances in sustainable aviation fuel (SAF) all the time.

Landside considerations

Following take-off aeroplanes are hundreds of feet above the airport location less than one minute into the flight. We know that inflight emissions disperse in such a way that they are not detectable at ground level, and ground taxiing is not in close proximity to houses or people in the community. In fact, it’s not aircraft that are responsible for poor air quality in and around airports – it is road vehicles.

The key to improving air quality for local communities is to reduce the negative impact of ground vehicles and traffic around the airport. Airports are reducing vehicle emissions with plug-in hybrid and pure electric vehicles (EVs) making up an increasing proportion of the road fleet, but the greatest impact will be realised by the thousands of passengers travelling to and from the airport.

That means thinking beyond the airport to a multimodal transport system that incentivises sustainable transport and greater connectivity through public transport.

In order to make a significant difference, investment is needed across infrastructure, from EV charging points on airport sites, to better rail connections and green corridors that encourage sustainable travel. The best recent example of this is The Elizabeth Line connecting East London to Heathrow Airport which opened in 2023 – making a rail journey to Heathrow feasible for many thousands of passengers and colleagues.

As part of Heathrow’s expansion plans, the airport designed a 20km ‘green loop’ around the airport to help connect communities, create positive opportunities for residents to stay active, and facilitate cycling or walking as a realistic alternative to driving.

Incorporating multi-modal access and green-blue infrastructure into airport design, alongside investment in connecting infrastructure, will be a key contributor to sustainable growth for the future.

The aviation industry has a responsibility to show it can strike a balance between environmental impact and permissible growth, but airports don’t have to choose between expansion or the environment.

By designing for efficiency across the industry, integrating built and natural infrastructure for electrification, future fuel readiness and climate resilience, we can grow responsibly. Done right, expansion will actually create opportunities for positive environmental and social outcomes.

There are myriad efficiencies which can be designed into airport expansion plans to deliver simultaneously for the environment and the economy. Only by allowing aviation to expand and develop – with appropriate environmental safeguards - will the industry be prepared to follow through on its environmental commitments.