Vectren Corp. has agreed to a three-year deal to remain the chief sponsor of the Dayton Air Show while the annual event expects a “slight loss” this year from lower attendance, according to an airshow official.

“The Vectren sponsorship is huge for the stability of the event as the title sponsor,” said Brenda Kerfoot, air show general manager. “Obviously, it is the top sponsor of the air show and it is significant.”

Both Vectren and the air show declined to say how much the sponsorship deal is worth. The energy company’s sponsorship began in 2001.

“It’s sort of the premier event of Dayton and it helps the community,” said Brandy Spainhoward, a Vectren spokeswoman in Evansville, Ind. “It brings in people from all over the country. We know from the past several years Dayton has taken a rough hit during the economic downturn and anything we can do to help the city of Dayton is a win.”

Hot and humid weather kept crowds away for the July 7-8 air show as temperatures hit the 90s and more than 100 degrees on the tarmac at Dayton International Airport in Vandalia. Turnout dropped 38 percent with 47,000 people passing through the gates for the weekend, according to air show organizers. Typically, about 75,000 people attend the performances.

“From the indication right now, there is going to be a slight loss (financially) this year which is somewhat expected because of the excessive heat,” Kerfoot said. Exact numbers won’t be known for weeks while bills continue to arrive, she said Thursday.

“We do have an adequate fund balance that we could weather a year like this with no problem,” she said. The air show declined to say how much the United States Trade and Air Show Inc., which organizes the air show, has set aside in reserve.

Next year, the show’s tentative dates are July 20-21. The exact dates won’t be set until December when the Air Force Thunderbirds release their performance schedule. The air show aims to attract the Thunderbirds as the headline act after the Navy’s Blue Angels performed this year, Kerfoot said.

The Dayton/Montgomery County Convention and Visitors Bureau estimates the air show has a more than $3 million economic impact on the Miami Valley.