MENLO PARK, Calif. — In classical mythology, Aquila is the eagle carrying Jupiter’s thunderbolts skyward. At Facebook, it is the code name for a high-flying drone, indicative of the social networking company’s lofty ambitions.

The V-shaped unmanned vehicle, which has about the wingspan of a Boeing 767 but weighs less than a small car, is the centerpiece of Facebook’s plans to connect with the five billion or so people it has yet to reach.

Taking to the skies to beam Internet access down from solar-powered drones may seem like a stretch for a tech company that sells ads to make money. The business model at Facebook, which has 1.4 billion users, has more in common with NBC than Boeing.

But in a high-stakes competition for domination of the Internet, in which Google wields high-altitude balloons and high-speed fiber networks and Amazon has experimental delivery drones and colossal data centers, Facebook is under pressure to show that it, too, can pursue projects that are more speculative than product.