Google’s parent company and its ambitious drone delivery project appear to have hit some turbulence.

Alphabet’s Project Wing drone project has cut staff, instituted a hiring freeze, and axed a partnership with coffee-chainStarbucks, Bloomberg News reported Tuesday. Alphabet and Starbucks are said to have tested a drone delivery program together, the report said, but it’s unclear what they delivered.

Separately, the Wall Street Journal reported Tuesday that Alphabet executives “pushed out” Project Wing’s former head Dave Vos as well as the drone project’s commercial executive Sean Mullaney in October. The report said that the two drone executives departures came amid some sort of conflict between drone engineers and the team responsible for trying to commercialize the initiative.

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Astro Teller, CEO of X, the Alphabet research unit that oversees the drone program, has taken control of the Project Wing drone initiative since Vos left.

Project Wing’s executive departures as well as the scaling back in staff and hiring signal that Alphabet’s drone delivery project may be experiencing challenges getting off the ground. In September, Alphabet partnered with Tex-Mex food chain Chipotle to use drones to deliver burritos to Virginia Tech students and staff.

Despite the apparent setbacks, Alphabet seems determined to push forward with its drone delivery project. In an interview with technology news site The Verge published on Tuesday, Teller gave no indication of any problems with the project, and only said that Alphabet must “make things that can successfully move long distances completely autonomously with very high levels of safety and reasonably inexpensively.”

A spokeswoman for X told Fortune in an email that, “Project Wing has the potential to remove a big chunk of the friction in how physical things are moved around in the world.”

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“What we’re doing now is developing the next phase of our technology and, as always, are thinking in a very broad way about all the potential use cases for delivery by unmanned aerial system,” the spokeswoman said.

Fortune contacted Starbucks sbux and will update this story if it responds.