Eastern Airlines' exit from the marketplace in the wake of the mechanics' and pilots' strike last month has created both headaches and opportunities for Delta Air Lines, Utah's predominant air carrier.

Fred Rollins, Salt Lake district marketing manager for Delta, said Delta's regional reservations center here has been fielding some 5,000 more calls a day from travelers since Eastern shut down operations and parent company Texas Air Corp. began negotiations to sell the beleaguered carrier.Eastern operated minimal flights out of Salt Lake International Airport prior to the shutdown, so there hasn't been a lot of slack to take up locally. But elsewhere, particularly in the East, Rollins said Delta has experienced significant increases in passenger volume - more than it can handle with available aircraft.

On the other hand, Delta takes no pleasure in Eastern's woes, said Rollins. "It doesn't help the industry's image when so many airlines are having difficulties," he said. "All I can say is we're doing very well and trying to mind our P's and Q's."

Rollins made his comments during an interview prior to the Utah Air Travel Commission's monthly meeting where he painted a rosy portrait of Delta as an airline undergoing rapid expansion in virtually every segment of its domestic and international business.

Rollins outlined dozens of new flights Delta is inaugurating now and in coming months, including new non-stop service from its Salt Lake hub to Sioux Falls, S.D., and two daily non-stops from Salt Lake City to Long Beach.

Delta is also moving closer to its goal of building Honolulu as a hub for Pacific operations by filing for federal route authority between Honolulu and Tokyo. Rollins said Delta wants to develop Honolulu as a key base of operations to Australia, Korea and other Asian cities.

Delta is currently seeking approval for service from Los Angeles to Sydney, Australia, via Honolulu. If that authority is obtained, the airline plans to implement Honolulu-Seoul service in 1991.

The airline currently operates more than 2,200 flights daily across its international route system. For the future, Rollins said, Delta is looking at Singapore, Bangkok and other exotic ports of call in the Pacific.

"I've never seen anything like it in my whole career," said Rollins of Delta's expansion activity. "It's really exciting."

At Salt Lake City International, Delta is winding down an $11 million construction project of a new maintenance facility and is set to begin building a $7 million ramp tower for use in controlling Delta aircraft taxiing in the terminal area. It will also house a new group room and a new hospitality room for Delta customers.

Last month, The Air Travel Commission released results of a $15,000 air fares study it commissioned from Washington, D.C.-based Kurth & Associates. The study was in response to complaints of soaring air fares since Delta established a Salt Lake "hub" operation and became the dominant carrier here after merging with Western Airlines in 1987.

That report thoroughly exonerated Delta from claims of price gouging. On the contrary, it found that Utahns are getting better - and in some cases cheaper - air service than other markets its size.

Nevertheless, some local air travelers - supported by a local weekly newspaper - have refused to accept the results of the study, saying it's a whitewash and fails to address the issue of reputed high employee salaries at Delta and the rapid escalation of fares on certain routes, such as the heavily traveled route from Salt Lake to Los Angeles.

Rollins conceded that some people will not be convinced by any proof to the contrary but said the support from the business community has been mostly positive since the report was published. He said he is glad to have the report and hopes the complaints will now abate.

"We want to get back to promoting Utah," he said.

He said news stories of high air fares, a "collapsing" Utah ski industry and other negative reports "are like shooting ourselves in the foot" when it comes to economic development.

"That kind of thing is dangerous to the Utah economy and our prospects of bringing new companies in here," he told commissioners.