The last four primary airports were opened during the 1970s.

It is one of the two primary airports in the Tokyo region.

For some time it was the primary airport in Brisbane.

Flight delays at 21 primary airports amount to 20,000 hours a year.

No primary airports had been built in Helgeland by the mid-1960s.

Parliament passed the proposal, which included building three of the intended nine primary airports.

Parliament passed his proposal, that included also building three of the intended nine primary airports.

Between 1947 and 1950, county officials expanded the small airport to become Detroit's primary airport.

Given limited land resources in Singapore, the airport was designed for both current and future needs as the country's primary airport.

It was never utilized as a primary airport due to its lack of paved runways.