It wasn’t until after WWII that London Airport – Heathrow began to take shape as a major transit hub for London. In 1946 Heathrow was just a small privately owned grass-airfield with little if any infrastructure and no real terminals. Actually, in 1946 when Ministry of Civil Aviation took over the site they erected a tent as the first terminal structure (no word what the departures lounge amenities were like). With the expected growth of post-war air travel London needed a facility that could expand with the demand; at the time the partially built Heathrow site was ideal. More than sixty years later and Heathrow is the busiest airport in Europe and one of largest in the world.
These two videos (and images) take an interesting look at the history one of the most travelled airports in the world.