United Airlines says it plans to operate over 3,500 daily domestic flights this December — its largest domestic schedule since the pandemic started. The carrier says holiday flight searches on its website are up 16% compared to 2019 before the pandemic.

The industry is optimistic said analyst Richard Aboulafia at Teal Group, but there’s also reason for caution.

“Well, just, you know, the summer experience really shows how quickly this can turn for better or for worse,” he said.

The delta variant tempered expectations for demand, said Madhu Unnikrishnan of Airline Weekly.

“The airline industry had pinned a lot of hope on Labor Day. And now it’s kind of moved that pin over to the holidays,” he said.

COVID-19 cases are falling in many places, so potential customers are surfing airline websites again. But Unnikrishnan said during the pandemic, people are booking their flights closer to when they fly.

“We’re still two to little more than two months away from the holiday period so it remains to be seen of people who are searching actually go through it buying tickets,” he said.

Normally, Unnikrishnan said, holiday trips would be booked by now. But this year, he expects people may wait till the last minute.