Facebook has made splashy announcements over the last four years about building a fleet of solar-powered drones, with wingspans bigger than a Boeing 737, beaming internet access to people around the world who can’t otherwise get online. (When you have as many users as Facebook, finding new ones requires some ingenuity.)

On Wednesday, the ambitious effort was halted.

Facebook announced in a blog post that it would no longer build the drones. The company said that it was still committed to the original goal of bringing more people online, but that it would instead rely on other companies to build aircraft. A plant in western England where the planes were being manufactured will be closed.

Mark Zuckerberg, Facebook’s co-founder and chief executive, had envisioned drones powered by the sun, flying for months without landing, 60,000 feet above far-flung areas. The aircraft filled a warehouse, but weighed as much as a grand piano. After a successful test flight in 2016, Mr. Zuckerberg hailed the project as “something that’s never been done before.”

But the drone initiative, Project Aquila, suffered several setbacks. One test flight ended with a crash landing and a broken wing. The initiative fell under the company’s Internet.org project to expand internet access in underdeveloped parts of the world, a controversial effort that critics called a ploy by Facebook to get new users.