How did airports come to be called ports, since few are near the sea. Why not airbase or airstation say?

The etymology of the suffix "port" is very extensive.

http://www.etymonline.com/index.php?term=port

At first, the places where planes took off and landed were usually called airfields. Only the largest ones, organizing long distance and international air travel and cargo handling were called airports because they did fulfill the role of ports. Airbases are specifically for armed forces. In each case, the generic "-field" was replaced with a more specialized existing term. In German, the distinction is still being made - general aviation facilities are called "Flugplatz" (airfield) and only large, commercial facilities are "Flughafen" (airport).

(Source: from parallel German etymology)

As commercial use of modern means of transport developed, trains started at stations, while buses and coaches also had stations. So after train station, bus station, why for aircraft did they not have air stations? I was on a boat tour of the Solent yesterday, and the (probably completely unreliable!) commentator explained that because the first commercial aircraft were flying-boats and used a base on Southampton Water, it became known as an air port.