But the ease of interisland hopping is beginning to diminish as the state's major interisland airlines grapple with a tough financial environment and begin coordinating seat capacity under a federal antitrust exemption.

What made it so easy for last-minute fliers were the many interisland flights with available seats. Advance-purchase coupons made it financially viable.

But that is also what made business tough for Hawaiian and Aloha airlines, who told antitrust officials during attempts to merge earlier this year that the interisland routes were unprofitable. As airlines have started more nonstop flights from the Mainland to the Neighbor Islands, demand for interisland travel also has waned.

As the carriers begin to pare interisland flights, frequent business travelers are finding it less convenient and more expensive to get work done. In the tourism industry, package tour sellers are growing worried it will become difficult to sell last-minute Neighbor Island visits.

"It's almost been like public transit to us — and on the Mainland it isn't that way," said Hawai'i Tourism Authority executive director Rex Johnson, also a former head of the state Department of Transportation.

"I think it will be more of a temporary shortage and a temporary inconvenience, until we learn this way of travel everybody else in the United States is stuck with."

Although both carriers said they would increase flights during peak holiday travel, they hope to reduce the surplus of interisland capacity in the long term.

After the first week of January, both airlines will reduce their interisland flight schedules to levels similar to those in early December.

"The ability to just jump on a flight that suits your schedule without booking in advance is going to get harder," said Hawaiian spokesman Keoni Wagner.

Aloha also has begun adjusting ticking pricing to make interisland flights less expensive for those who book in advance.

Beginning tomorrow, Aloha will offer seven-day advance reservation tickets for $63 and three-day advance reservation tickets for $67. Coupons and tickets requiring no advance reservation or purchase will cost $73.

"We do recommend that passengers plan ahead, book as far ahead as possible," said Aloha spokesman Stu Glauberman. "This is just a necessary part of restructuring our business so that it is profitable and more efficient and can serve the needs of the state far into the future."

The changes could potentially change significantly the behavior of Hawai'i's interisland travelers.

Customers who established loyalty to either Hawaiian or Aloha are finding it more convenient to buy both airlines' coupon books.

"People will need to learn to fly both airlines," said Robin Graf, general manager of the Outrigger Waikoloa Beach hotel, who commutes between work on the Big Island and home in Honolulu several times a week.

Graf and others are taking the hint from the carriers' pricing changes, and plan to cut down their use of coupons.

"They're telling us coupons are gonna probably go away, and the cost is going up on them," said Graf, who plans to shift to e-ticket reservations instead.

Some fliers say they have had to adapt to delays as flight crews deal with fuller planes and everyone adjusts to schedule changes on top of heightened security.

To make a 5 p.m. appointment in Honolulu, Graf used to be able to take a 3:30 flight. Now he needs to leave at 2 p.m.

"I've missed so many meetings in the last three months," he said. Scheduling difficulties drove him to plan all of his flights for December at the start of the month.

"That's hard to do because a lot of events come up," said Graf, who has made more than 100 round-trip interisland flights this year. "So I'm gonna have to pay the premium — which I don't think is fair, especially for people who fly as much as I do."

Others report similar adjustments, including Graf's boss, Outrigger Enterprises Inc. president David Carey.

Carey said he used to do "gobs of day trips, but I don't think I'm going to do that anymore."

The new challenges and costs of interisland flying could feed the trend of traveling less and teleconferencing or e-mailing to rein in costs.

For some business people, however, that's not an option.

"I'm a personal person — I like to meet face-to-face — and I still think that's a big part of our company," said Graf's co-worker, Outrigger Wailea Resort marketing manager Kathy Dziedzic.

The recent price increases for flight coupons will have an impact on travel expenses, Dziedzic said. "Even if it's only $10 (more), that adds up."

Rep. Sol P. Kaho'ohalahala, D-13th, recently won with his seat in the Legislature the task of navigating his district — East Maui, Moloka'i and Lana'i.

"Try to figure that one out," said Kaho'ohalahala, who lives on Lana'i and is looking for a house on O'ahu because flights don't allow him to travel easily to committee hearings and return home the same day.

To get from Lana'i to Maui — about nine miles — he has to connect through Honolulu.

Some people in the tourism industry worry that residents won't be the only ones deterred from interisland travel. Tour package sellers say interisland flight cuts might mean fewer options for their customers who want to visit multiple islands.

Japanese tour wholesaler JTB sells overnight Neighbor Island visits and one-day Neighbor Island excursions. Tour planning and marketing general manager Yujiro Kuwabara said he was concerned about the flight cuts and changes in pricing.

JTB used to control a block of seats on interisland flights, but with the limited number of available seats, it may have to limit its number of passengers.

Destination management firm Mary Charles & Associates, which organizes tours for visitors after arrival, has started to have difficulty getting Neighbor Island flights.

"We are already experiencing problems where we can get them there but we can't get them back, or the other way around," said president Chris Resich.

He said about 12 percent of his customers choose Hawai'i, then decide they want to travel to a Neighbor Island.

"They still want to go and see the volcano, or they like going to see Waimea Canyon on Kaua'i, so that whole one-day tour travel is a very important market," Resich said.

He even has had problems moving his staff around the Neighbor Islands, even though he's in the travel business.

"We need staff on every island. We've got to get them there, so we are scrambling and are frequently having to pay a higher fare, which is impacting us on the cost side," Resich said.

"I do realize that both interisland carriers have been operating at a loss in the Neighbor Island market, so I'm not quite sure what the right solution is. But there needs to be some accommodation."

Debbie Weil-Manuma, who runs Maui destination management company Weil & Associates Inc., said fewer flight options make meetings hard to manage.

In some cases, leaving Maui with a coupon may mean waiting nearly three hours for the next flight.

Neighbor Island tourism businesses particularly regret the cuts in MauiiBig Island flights, because some periods require that travelers fly via O'ahu.

"If you're a tourist and you want to do a two-island trip, you almost have to take a whole day out of your vacation to travel. I think we'll see that whole segment (of the travel market) go away," Graf said.

Some say Hawaiian and Aloha should not be allowed to cooperate and reduce interisland flights. Rep. Chris Halford, R-11th (S. Maui), said he was lobbying the federal government to end the practice.

"We have less service that costs more," Halford said. "The reason to allow a monopoly has passed ... it might have been appropriate a year ago, but it's not appropriate today."

Others, who compare interisland air service to state highways, say Hawai'i residents must have easy access to that transportation system.

"That's a public policy question, and that's a big one," Carey said.

Taxpayer dollars also are at issue.

"If we want to call them public transportation," Johnson said, "then we need to be willing to pay for public transportation."