• Frontier Airlines posted better-than-expected results.
• The carrier warned that the coronavirus delta variant has weighed on bookings over the past week.

Frontier Airlines posted better-than-expected quarterly results but warned that the Covid delta variant is hurting demand.

Frontier said Wednesday it expects, at best, to break even in the third quarter, compared with a previous forecast to post a profit, because of the fast-spreading variant.

"Within the last week, we have noted softening in the level of bookings over seasonal norms that we believe is directly related to the increased COVID-19 case numbers associated with the Delta variant," the carrier said in a quarterly report. "The impact of the Delta variant on bookings, and the duration of that impact, are difficult to predict."

Shares were down more than 1% in Thursday morning trading.

CEO Barry Biffle said the widespread availability of vaccines will likely blunt the effect of the delta variant.

Denver-based Frontier, which went public this spring, reported net income of $19 million for the second quarter, thanks to a boost in federal aid. That compares with a loss of $50 million a year earlier. Revenue nearly tripled to $550 million in the second quarter from a year earlier. That was above the $548.4 million analysts expected.

Stripping out one-time items, Frontier's per share loss was 24 cents a year, narrower than the 30 cents analysts expected.

Correction: An earlier version misstated how many earnings calls Frontier has had.