In view of the fact that every homeowner within earshot of an airport is dead set against any additional runways or extensions being built, today’s invention offers a simple alternative.
If quite substantial aeroplanes can take off, using a steam catapult, from the deck of an aircraft carrier, then surely a similar arrangement could be used for civil airliners? This would allow runways to be made less than half current size. A ground-based catapult system, using a shallow ramp, could be made extremely powerful and might allow the aircraft’s engine load at take-off to be much reduced (cutting fuel mass to be carried and also the enormous noise of getting airborne).
An arrestor hook mechanism would be needed for landing, but at least the technology is well-established and surprisingly reliable.