The airport in Kona on Hawaii is built on a lava flow from Hualalai’s last major eruption about 200 years ago. Hualalai is still considered an active volcano, too. Maybe they’ve got a force field they haven’t told anyone about.
Hawaii has fairly liquid lava, which means that the dissolved gas can escape safely and not build up pressure for a big sudden explosion. Accordingly, while the airport may not be safe, the people should be since they can move away from any incoming lava in time.
The volcanoes with more viscous lava (such as Vesuvius) are much more dangerous in comparison.