Airlines with Japan destinations anxiously watch radiation levels – and ticket sales

Thousands of travelers jammed Tokyo's Narita International Airport again Thursday in attempt to flee Japan amid a worsening nuclear crisis at the Fukushima Daiichi atomic power plant.

The exodus – along with concerns about levels of radiation reaching Tokyo – has caused many airlines to rethink their Tokyo routes and schedules. And the entire airline industry seems to be anxiously eyeing the demand for flights to the regional hub.

According to a statement on its website, German airline Lufthansa is rerouting all of its Tokyo-bound flights to Osaka and Nagoya, both south of Tokyo, at least until Monday, March 21. Dutch airline KLM followed suit.

Air France, Swiss Air, and British Airways are among the airlines continuing their service to Tokyo, but they are including stopovers in other Asian cities so that their flight crew can switch over there instead of spending a night in Tokyo, according to their websites.

According to Bloomberg, Cathay Pacific Airways, Asia's third-largest airline, reported that they are seeing climbing numbers of vacant seats on their Japan-bound flights but mostly full flights out of Japan. Its website is reporting some delays in the flight schedule, but no reroutings or additional stopovers. It is also offering special one-way fares from Japan.

Meanwhile, Singapore Airlines is delaying the launch of Airbus A380 service to Japan because of the overall decline in demand for flights there, according to Reuters.

Whether airlines operating flights to Japan will face a substantial revenue decrease on those routes remains unclear.

Among US airlines, overseas routes such as the Japan ones are coveted because of a lack of competition from discount airlines, which allows them to keep their prices high, according to Bloomberg.

But United Airlines was offering round-trip tickets from San Francisco and Los Angeles to Tokyo for less than $1,000 Thursday – low for the industry:

"A walk-up fare below $1,000 is quite low and likely related to a drop in demand," said Dan Toporek, a spokesman for online travel agent Travelocity.com. "It’s too early to tell what the long-term impact will be."

The Bloomberg US Airlines Index slumped 6.4 percent from March 11 through yesterday, outstripping the 3.6 percent drop for the Standard & Poor’s 500 Index. Delta’s 9.2 percent slide was the most among 12 carriers in the Bloomberg gauge, followed by the 7.7 percent tumble for United Continental.

Continental Airlines was the first US airline to disclose that demand for flights to Japan was on the decline, according to Bloomberg. It hasn't made any changes to its schedule yet, but may cut some flights to Japan based on demand.

American Airlines is also keeping its normal flight schedule to and from Japan, so far.