Civil engineering and airport construction had relatively little to do with each other until the late 1930s.
Although the Wright brothers took their historic first manned flight in 1903, it was not until after the end of the Second World War that commercial air travel really began to catch on.
Within two decades air travel had become an indispensable 20th century transport mode, while airports were providing a growing challenge for civil engineers in Britain and abroad.
Before the 1930s, air travel was expensive and aircraft capacity limited. Most aircraft were light enough to take off and land in grassy fields and there was no such thing as a passenger terminal. People wealthy enough to travel by air checked in for their flights inside customs tents before making the short walk to the aircraft.
The Second World War changed all that. Airfields - many originally developed by local authorities - were commandeered by the Royal Air Force. The RAF needed them to handle heavier fighter aircraft such as Spitfires and Hurricanes, weighing between 2,700kg and 3,200kg and, by the end of the war, heavy American bombers weighing 13,500kg. Grass fields were never going to stand up to the pounding from these aircraft, so the Air Ministry launched a huge runway construction programme. Concrete was the favoured material as it was hard-wearing and drained easily.
Between 1939 and 1945 contractors such as John Laing, Richard Costain, Sir Robert McAlpine and W&C French built a staggering 96, mainly concrete paved, airfields for £200M (Second World War prices). In all, these amounted to the equivalent of 6,348km of three-lane motorway.
Immediately after the war, many airfields reverted to commercial use. Air traffic grew exponentially, outstripping forecasts as air travel became cheaper and aircraft bigger.
Passenger growth spurred a massive, ongoing construction programme as key airports such as Heathrow, Manchester and Gatwick battled to raise capacity. Increasingly, large passenger aircraft needed longer runways and traffic increases put passenger terminals under pressure to cope.
Manchester Ringway's runway had to be lengthened four times between 1951 and 1969 when the first Boeing 747 jets came in. The same airport also saw passenger numbers increase from 34,000 a year in 1947 to 945,500 in 1961. In London, three passenger terminals were built at Heathrow between 1951 and 1969, raising handling capacity from 1M a year to 30M. Nowadays, the airport can handle 65M passengers a year.
Airport construction boomed from the mid-1950s, drawing increasingly on civil engineers' planning, contracting and design expertise. Associated road and rail links were also needed as Britain's airports challenged railway stations as the century's great transport interchanges.
In 1971, pressure on London's airports had reached the point where runway capacity was restricting traffic growth. As a result, the Government announced plans to build a London airport at Maplin.
This announcement failed to anticipate the combined influences of new aircraft designs, environmental opposition and the oil shock of the early 1970s.
The introduction of high capacity wide-bodied jets reduced pressure on existing runway capacity to the point where new runways were considered unnecessary, at least in the short term.
Strong environmental opposition and the economic impact of the oil crisis were further nails in Maplin's coffin, and the Government decided instead to build Terminal 4 at Heathrow.
In the ongoing battle to boost capacity, engineers and architects had to design terminals with room for expansion.
At Heathrow in the 1950s the Air Ministry decided there was enough room to house all passenger handling facilities in the 24ha diamond-shaped central terminal area. The plan was to start with the Europa building (now part of Terminal 2) and add other terminals.
But traffic growth was so rapid that by 1969 Heathrow's central terminal area was clogged with three passenger terminals, an air traffic control centre and car parking. As a result, Terminal 4 had to be constructed on the airport periphery.
Expansion at Gatwick was also hampered because the first terminal was sandwiched bet-ween the runway and the London to Brighton railway. Little could be done to expand existing terminals without disruptive demolition. Instead, extra capacity was introduced by removing non-core administrative offices and simplifying floor plans. At Heathrow, what is now Terminal 1 was perhaps ahead of its time when opened in 1961. The steel framed building had few vertical columns, making it easier to reconfigure space. A similar approach can be seen at Terminal 4, designed by Scott Wilson Kirkpatrick and built by Taylor Woodrow. BAA originally conceived T4 as a concrete structure, but eventually chose a steel frame capable of longer spans.
When Stansted was developed 10 years after T4, British terminal design had progressed to a new level. The ingenious structural steel trees, developed by engineers at Ove Arup & Partners, ensured the availability of even more free floor space.
By the 1990s, the battle for more runway space had resurfaced at Manchester. Heathrow operator BAA argued that the answer to increasing aircraft capacity was a fifth terminal rather than another runway or airport. But Manchester, with only one runway, was faced with a 150% increase in passenger traffic by 2003 and its owner, Manchester City Council, had to overcome opposition from environmentalists - who occupied parts of the extension site - before it got its way.
Now, pressure for airport terminal capacity continues to outweigh the need for new runways, as passenger jet capacity grows. BAA's argument in support of Heathrow's Terminal 5 has been that it is needed to handle growth in passenger numbers from bigger capacity jets.
As the century comes to an end, British engineers have finally been given the chance to design and plan an airport from scratch. In Hong Kong, engineers at Greiner Maunsell had the luxury of planning a purpose built, state of the art airport in the sea at Chek Lap Kok.
The result is a massive £2.3bn transport hub, with the combined capacity of Heathrow and New York's JFK airports, and scope for expansion. If it keeps up with demand, Chek Lap Kok will probably be criticised for being too big.