Before takeoff, Delta wants its New Haven business travelers to do more than just stow their luggage in the overhead bins and fasten their seatbelts tightly across their laps. The airline wants a guarantee that any expansion to Tweed-New Haven Regional Airport will not stall in midair.

The Regional Growth Partnership — an economic development group focusing on New Haven and surrounding suburbs — is trying to convince Delta to fly into Tweed by asking area businesses to commit to booking a certain percentage of their flights over the next year with Delta. If the offer is accepted, Delta flights could begin departing from Tweed as early as Aug. 30.

Delta’s revenue target for the route is $1.9 million a year, said Susan Godshall, senior vice president of the Greater New Haven Chamber of Commerce. Godshall said the airline would fly three flights in both directions between New Haven and Cincinnati each weekday and slightly fewer on weekends. With that number of flights, the target could be met if those flights were on average 80 percent full.

Godshall said flights from Tweed may cost slightly more than those out of Hartford’s Bradley International, but the companies should more than recover that cost through the time they save.

To achieve this goal, the region’s eight largest groups — including Yale — that routinely book business flights were asked to shift their trips to depart from Tweed rather than New York area airports and from Bradley, Godshall said. In a meeting two weeks ago, 70 smaller companies were also asked to get involved in the proposal.

Yale Vice President Bruce Alexander, the director of the Office of New Haven and State Affairs, said in an e-mail that increased air service would greatly benefit the region.

“The University will do its part in supporting Delta’s entry into this market if we are able to work out an agreement to start service,” Alexander said.

The Regional Growth Partnership is scheduled to submit the plan to Delta by mid-April. If Delta agrees to the proposal, flights could begin out of Tweed before Sept. 1.

“Delta is anxious to hear from us,” Godshall said.

The war in Iraq could decrease the plan’s chances of success. While Godshall said she had received no indication Delta was planning to pull out, she said they could do so for perfectly good reasons that have nothing to do with New Haven in particular.

“Since the war in Iraq, the airline business has gotten even worse,” Godshall said. “Any new routes from any new airline are less likely than they were a week ago.”

The airline maintained that no agreement had been made.

“We have not made any announcement regarding service to Tweed-New Haven Airport,” Delta spokesman Katie Connell said.

Godshall said bringing in Delta would benefit New Haven in the long term by increasing competition among airlines in local airports.

“Once one [airline] opens a new route, the others start sniffing around because they want a part of it,” Godshall said.

In addition, the new Delta route would help establish Tweed as an “easy-in, easy out” regional jet airport, Godshall said. The current US Airways flights, on the other hand, use prop planes.

Godshall said Continental Airlines was also considering a new route from New Haven to Albany. Continental spokesman Rahsaan Johnson said its partner CommutAir, which flies out of Albany, was not looking to expand its regional flights in the Northeast at this time. But he said Tweed New Haven is “on the airline’s radar screen for future growth.”