Frontier said in a tweet just after 8 p.m. EST that a Microsoft outage was causing the issue, and also affecting other companies.
The FAA said the ground stop was canceled about 10:30 p.m. EST.
Booking, check-in and access to boarding passes were also affected by the outage, Frontier said.
Hours after the Frontier grounding, IT outages were reported across the globe and American Airlines, United and Delta asked the FAA for global ground stop on all flights, according to an alert from the FAA on Friday morning. As of Friday morning, flights in the air will stay in the air, but no American, United or Delta flights will take off.
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According to FlightAware, initially 103 Frontier flights (13%) were canceled and 231 flights (30%) were delayed.
Frontier later said its systems were normalizing, and flights were resuming.
A Federal Aviation Administration advisory said no other airlines were impacted.
Microsoft also tweeted users might have trouble accessing various Microsoft 365 apps and services.
This is a developing story; check back for updates.