G'Day consumers, airfares to Down Under are on their way down.

Travel between Sydney and Los Angeles, considered one of the world's more popular but most expensive routes, soon might be getting more competitive for airlines and less expensive for passengers.

After a decade of wrangling, Australian and U.S. negotiators agreed to a landmark aviation pact to open their skies to each other's airlines, and Los Angeles International Airport might be the big winner. It is the nation's busiest hub for flights to and from Australia.

The deal, which must be ratified by both governments, would open the route to more airlines, including a fare-slashing carrier started by British billionaire Richard Branson.

Some analysts predicted that fares, which hover at $1,500 for the least expensive round-trip coach ticket between Los Angeles and Sydney, could fall below $1,000 — in line with other international flights of similar distance.

Corporate travelers buying business-class tickets for as much as $18,000 could see fares fall even further, perhaps by as much as several thousand dollars.

"It's great news for consumers and the travel industry," said Diane Embree, a travel consultant for Michael's Travel Centre in Westlake Village, Calif. "Lot of people want to go to Australia but because there is limited competition, airlines have been able to charge whatever they want."

L.A., a key gateway to Australia, is expected to be a major beneficiary of the so-called Open Skies Agreement, which was hammered out over three days in Washington, D.C.

The agreement "begins a new era where American and Australian consumers, airlines and economies can enjoy the benefits of lower fares and more convenient service," U.S. Transportation Secretary Mary E. Peters said.

In an unusual duopoly, only two airlines have been allowed to offer nonstop flights between the Mainland U.S. and Australia. And because of the demand for travel between the two countries, Qantas is now the largest foreign-based carrier at L.A. International, operating three flights a day with 747 jumbo jets often flying full.

Last year, it flew more than 1.2 million passengers between L.A. and Australia, now considered one of the most profitable routes in the world. While the U.S.-Australia flights account for only a fraction of overall operations, they generated about 15 percent of the airline's profits.

U.S. carrier United Airlines, which has one daily flight from L.A. International to Sydney, is the only other airline that has been allowed to offer nonstop flights between the Mainland U.S. and Australia.

In an earlier interview, Branson said his low-cost airline in Australia, Virgin Blue, has applied to fly between Sydney and L.A., launching the first volley in what is expected to be an intense fare war. The trans-Pacific route, to be operated by Virgin Blue's new subsidiary V Australia, could begin as early as mid-October.

The agreement also could help increase chances of L.A. International becoming a hub for Branson's ambitions to form a global carrier. L.A. officials have been talking with both Virgin America and Virgin Blue to co-locate gates. Branson's Virgin Atlantic, which flies trans-Atlantic flights from London to L.A., would be next door.

With all three airlines nearby, passengers from both sides of the globe could connect at L.A. International to destinations in the U.S.

Such a move could provide an economic boon for the region, said Jack Kyser, chief economist for Los Angeles Economic Development Corp. The research outfit estimates that adding just one daily international flight at L.A. International could pump $623 million into the economy annually.

But U.S. carriers are not expected to enter the fray at least for now. Several airlines would not say whether they would start an Australian route, but analysts said the airlines probably will balk at the moment because fewer U.S. travelers are flying overseas amid a weak dollar and a slowing domestic economy.