Terror treat in New York and DC, a power outage grounds flights at San Diego airport, Google buys Zagat, a Swiss agency reveals the world's safest airlines, an Australian research centre identifies the world's busiest airline routes, and more. Here is what travellers are buzzing about:

Will it be safe to travel on 11 September this year?
US federal officials have warned of "a credible but unconfirmed terrorist threat to use a car bomb on bridges or tunnels in New York City or Washington, D.C.," reported NBC News, citing an anonymous official as putting the threat on a scale of "5 or 6 out of 10" -- with 10 being certain attack. The warning follows an earlier travel alert issued by the US State Department: "In the past, terrorist organisations have on occasion planned their attacks to coincide with significant dates on the calendar." One thing seems certain amid all the concerns: there will be delays associated with increased screening at access points to airports and other transport facilities in major US cities around the anniversary of the 2001 attacks.

San Diego airport and train service disrupted
A power outage yesterday afternoon in parts of the US Southwest grounded all flights in San Diego, California, the nation's eighth largest airport. As of this writing, San Diego airport was fully operational, with some cancellations and delays and  so travellers should check FlightStats or their airline or Amtrak for details. 

Revealed: The world's busiest airline routes
They're all in Asia, according to the Sydney-based Centre for Aviation. The busiest route, defined as having the most number of seats filled on flights scheduled per route, is in Japan, between Tokyo's Haneda Airport and Sapporo. Next busiest routes are in South Korea (Seoul/Jeju Island), Japan (Tokyo/Fukuoka), and Australia (Sydney/Melbourne). 

Revealed: The world's safest airlines
The Geneva-based Air Transport Rating Agency has released its Holistic Safety Rating 2011 report. Based on an analysis 15 sets of safety data, the report names the safest major commercial airlines, in alphabetical order: Air France-KLM, American Airlines, British Airways, Delta, Japan Airlines, Lufthansa, Southwest Airlines, United/Continental and US Airways. 

Google buys Zagat
The search giant has bought the 33-year old recommendations and rating company, after having failed in its effort to buy similar ratings from the online listings site Yelp. Industry insiders at trade publication Tnooz asked, "Will it now emphasize Zagat reviews over those from TripAdvisor and Yahoo in a similar manner to the way it gives preference to Google user reviews over third-party reviews in Google Hotel Finder?" Good question.

The mega re-tweet
We scour Twitter to highlight a standout travel tweet.
"@Marilyn_Res Hi Marilyn! I still have a mental image of you cycling across DC in the rain in your pajamas!"
-- @BertieWWooster a.k.a., Bertram Wilberforce ‘Bertie’ Wooster, the fictional character created in the early 20th-century by British writer PG Wodehouse. It turns out he has a Twitter account and is fond of Marilyn Resnik, the chief of research at National Geographic Traveler magazine (US).

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