A cluster of satellites launched over the weekend is intended to begin overhauling the way air-traffic controllers track planes around the world, but the U.S. may not take a lead role in undertaking those changes.

For decades, controllers have used ground-based radar to direct planes over land. More recently, they have been finding aircraft locations via global positioning satellites, or GPS, but they can do so only over land or near the shore. There has been no real-time ability to track planes in flight over oceans, which...