In 2020, how many of the world's sovereign states had no airport for fixed-wing aircraft?

A sovereign state is a political entity with a permanent population and represented by one centralised government with sovereignty over a defined territory and the capacity to enter into relations with other sovereign states. It is normally understood that a sovereign state is politically independent. However, there are five sovereign states that are dependent on others for airport services (although they have heliports to make connections):

Andorra has three private heliports, one of which is a hospital helipad. A "National Heliport" is planned but in 2020 the process was stalled. By both population and land area, it is the largest country not to have an airport. Barcelona and Toulouse airports are the most common choice for long-distance travel to Andorra.

Liechtenstein has a heliport in the southern town of Balzers. The nearest major airport is Zurich Airport in Switzerland.

Monaco has Monaco Heliport in the district of Fontvieille (pictured). The nearest airport is Nice Côte d'Azur Airport in France.

San Marino has a heliport in Borgo Maggiore. The nearest airports are at Rimini and Bologna, both in Italy.

Vatican City has Vatican City Heliport in the western corner, used by visiting heads and Vatican officials. The nearest airports are Rome Ciampino Airport and Rome–Fiumicino Airport in Italy.