A flight departs from Logan Airport's runway 27 over Boston Harbor. File photo

Buoyed by a passenger surge in July, Massachusetts Port Authority officials are optimistic that the return of air travel through Logan International Airport is outpacing their earlier projections even as the Delta variant portends a forthcoming slowdown.

In July, Logan served 2.6 million travelers, beating the agency’s 1.67 million estimate by 55 percent, Massport CEO Lisa Wieland said at a Thursday board meeting. That brought in more parking and concessions revenue than anticipated, helping push monthly revenues $28 million above expenses.

That pace looks unlikely to continue into the ensuing months. Bookings are now “softening” after the more infectious Delta variant fueled an increase in COVID-19 cases and hospitalizations, Wieland said, adding that the decision some major employers made to delay office reopenings also slowed the return of business travel.

Transportation and port officials said Logan remains on track to recover fully from COVID-19 impacts in the next three to five years. Massport projects that passenger volumes at the region’s biggest airport will still surpass projections in September and October despite the slight backslide, according to data Wieland presented.

“Looking ahead, we remain cautiously optimistic about our three- to five-year recovery plan,” she said. “Even with the falloff from the summer activity, we are still trending above our most likely case scenario.”

Massport’s financial situation is also looking better. Officials initially projected a deficit of more than $100 million for fiscal year 2021, which ended June 30, but Wieland said that a combination of better-than-expected early summer travel, high volumes of container shipping, and cost controls shaved the deficit to $22 million.

The increase in travel and stabilizing Massport finances prompted Fitch Ratings in August to affirm the agency’s bond rating at AA and adjust its ratings outlook from “negative” to “stable,” Wieland said.