Airline shares around the world largely took another hit on Tuesday on fears of steep falls in business and leisure traffic because of the swine flu outbreak.

Among the shares of the U.S. carriers, industry leader Delta Air Lines fell almost 10 percent and US Airways Group fell 4 percent.

American parent AMR Corp and Southwest Airlines bucked the overall trend and ended a respective 1 percent and 3.9 percent higher, but they were not enough to help the AMEX airlines index <.XAL>, which ended down 2.6 percent.

Cruise and hotel operators, which took a severe beating on Monday, bounced back, with Carnival Corp and Royal Caribbean Cruises Ltd up 3.9 percent and 3.3 percent, respectively.

The swine flu was expected to cause customers to cancel travel plans, sending shares down in double-digit percentages on Monday, but on Tuesday most reports said travelers were largely keeping their current plans in place.

But fears remained that future bookings and travel plans could change, based on the spread of the flu.

As more news comes out on swine flu, it's more apparent to investors that it's a localized thing, said Jim Corridore, an analyst with Standard & Poor's Equity Research. It's mostly in Mexico where at least U.S. airlines get a very small percent of their revenues. And it's likely to be of short-term duration.

Matthew Jacob, an analyst with Majestic Research, said the Monday selloff could have created a buying opportunity for U.S. investors.

Stocks took a big hit yesterday and they're not fully recovering that amount ... there's still some risk out there, he said.

But I do think that there's a feeling that some of the (swine flu) concerns may be a little bit overblown in the travel industry, he added. It does not seem that it's going to stop the recovery that we had been seeing elsewhere in the industry.

Swine flu has killed at least 149 people in Mexico.

HOME AND ABROAD

In Europe and Asia, airline stocks posted a second -- albeit more modest -- day of declines following comments made by Geneva-based International Air Transport Association that a possible swine flu pandemic could bring more pain.

Anything that shakes the confidence of passengers has a negative impact on the business. And the timing could not be worse given all of the other economic problems airlines are facing, IATA said in its monthly traffic statement.

British Airways and Air France-KLM -- a combination of two networks that collectively have the largest European exposure to Mexico -- fell about 5 percent and 2 percent, respectively.

In Asia, Hong Kong's Cathay Pacific <0293.HK>, which bore the brunt of the SARS crisis in 2003, closed down 0.95 percent after sharp earlier falls, and Air China <0753.HK> fell 7 percent.

Stone Lin, an airline analyst with Yuanta Securities in Taiwan, said the flu outbreak could dim hopes for summer travel.

The summer months of July-September are typically the peak season for most airlines, with most bookings beginning right now, the analyst said.

With sentiment so weak, and worsened by the swine flu issue, it's unlikely anyone is going to go rushing to book holidays or corporate travel, which means the second half of this year won't be pretty for most airlines, he added.

IATA, which represents 230 carriers, said airlines could lose $4.7 billion this year before any impact from swine flu.

But Michael O'Leary, the head of leading European low-cost airline Ryanair , sounded a contrarian note.

Are we going to die from swine flu? No. Are we in danger of SARS? No. Foot and mouth disease? No. Will it affect people flying short-haul flights around Europe this summer? Thankfully, no, he said.

TWO HEADWINDS

During the SARS outbreak, which began in China, airline traffic in Asia halved, and airline stocks tumbled 25 percent or more.

(For related GRAPHIC, click http://graphics.thomsonreuters.com/apr09/EQ_AIRLNS0409.jpg)

Most industry watchers, however, said it was still too early to say how big the swine flu risk could be to airlines this time.

The overall situation is weaker now ... because there are two headwinds the airline industry is facing: one is the global recession and now this outbreak of swine flu, said Daphne Roth, analyst at ABN Amro private bank.

But she added the current situation was also different from SARS, as information about the illness is coming out faster.

There is a lot of fear out there right now and I think we've got to see if it gets much worse or the same or better over the next few weeks, said Clay Jones, chief executive of Rockwell Collins, a U.S. supplier of parts to Boeing Co and EADS unit Airbus.

If Mexico stays the center of attention, I'm not overly concerned, Jones added. If it spreads widely in the United States, obviously that's a much different situation.

(Writing by Tim Hepher in Paris, Doug Young in Taipei and Karen Jacobs in Atlanta; additional reporting by Reuters bureaus across the world; editing by Will Waterman, Patrick Fitzgibbons and Steve Orlofsky)