Hollywood is bracing for a weekend of disruptions after the Federal Aviation Administration grounded all flights in the United States on Friday, throwing travel plans into question for talent, executives and buyers headed to and from Los Angeles and New York for one of the busiest stretches on the industry calendar.

The FAA says all U.S. flights are grounded until further notice “due to extraordinary circumstances and for reasons of safety.”

The cause is not yet clear, but an FAA spokesperson says a communications problem is affecting the Air Route Traffic Control Centers, which handle flights moving across the country. Preliminary reports indicate it is not a cyberattack, according to law enforcement officials and media outlets. The rare ground stop, which was announced just after 1 p.m. PT, is the first full stoppage since 9/11 and more than 7,800 flights across the U.S. have already been delayed, according to FlightAware.

On Sunday, the Academy of Motion Picture Arts and Sciences is set to hold its 17th Governors Awards at the Ray Dolby Ballroom at Ovation Hollywood, where honorary Oscars go to eight-time nominee Glenn Close, legendary Director Ridley Scott and Floyd Norman, Disney’s first Black animator. Killer Films producers Christine Vachon and Pamela Koffler, longtime champions of independent film, receive the Irving G. Thalberg Memorial Award.

The evening doubles as one of the season’s most important campaign stops, with contenders working a room filled with the Academy’s governors, three from each of its 19 branches, representing everyone from actors and directors to artisans and executives.

Variety has reached out to the Academy for comment.

The grounding will also affect buyers and sellers at the final days of the American Film Market, which runs Nov. 10-15 at the Fairmont Century Plaza in Century City. With international sales agents, buyers and financiers due to fly home this weekend, many of them could find themselves stuck in Los Angeles.

Numerous FYC events are also taking place around Los Angeles, with awards contenders frequently criss-crossing the country during the busy pre-Thanksgiving period.

On Saturday, Netflix will host the official Academy screening for AMPAS members for David Fincher’s highly anticipated “The Further Mis-Adventures of Cliff Booth,” written by Quentin Tarantino, in which Brad Pitt reprises his Oscar-winning role from “Once Upon a Time … in Hollywood” (2019).