Battling insurgents in Afghanistan is often nasty and dangerous. But for reasons not entirely clear, U.S. troops seem to be getting hassled, coming and going, by their own country’s airlines.

This week finds Delta Airlines apologizing to service members for the second time in 10 weeks. This time it’s for charging a group of soldiers returning home $200 for a fourth checked bag — for a total of $2,800, the soldiers estimated.

Then, after some of the soldiers, who were on a flight from Baltimore to Atlanta, complained in a YouTube video — since removed — that went viral on the Internet, Delta announced on its blog that it was changing its three-bag policy for the military. The airline said it would allow military personnel traveling on orders to check up to five bags in first and business class.

But it seemed for a while that troops flying coach could only get three for free. Someone must have figured out that most troops tend not to fly first class, so the airline then said four bags would be fine even for those traveling coach.

The hubbub reportedly sparked a number of airlines to affirm or change baggage policies so that troops traveling on orders could check four or five bags for free. Delta is offering to compensate the soldiers affected in the most recent situation.

Loop Fans may recall our March 29 column about Marines stationed in Hawaii being hit with higher ticket prices — up to $900 in one case, we were told — when the Pentagon changed their deployment dates.

That change meant the Marines and sailors had to rebook their pre-deployment flights home before they headed to one of the most dangerous places in Afghanistan.

Several airlines, including U.S. Airways, United Airlines and Delta — waived the $150 change fee, but apparently would not waive the substantially higher ticket prices.

Seems like it may be time for everyone to get together and sort all this out.

Fish story

The blistering heat this week beckons us to area beaches to cool off. And when we hit the surf, some of us will doubtless remember Bruce, the giant shark in the movie “Jaws,” and we’ll look around.

Do not be afraid. Unless you’re somehow mistaken for a seal, you should be fine. Turns out, sharks are less dangerous to humans than we are to them, according to a new book by our colleague Juliet Eilperin.

“They’re not exactly cuddly,” she explained, “but only a small percentage are dangerous. Like your average House member.”

In the book, Eilperin charts the complicated shark/human relationship through the years and takes us on several fascinating trips, including one in which she faces down a great white off the coast of South Africa and another ad­ven­ture canoeing with a Papua New Guinean who summons sharks in the sea.

Sometimes things got really dicey. Take, for example, the time she encountered Rosie O’Donnell out driving a motorboat with friends off Star Island near Miami.

As it turns out, overfishing has caused the world’s shark population to plummet dramatically. Humans are eating them — not the other way around. There’s talk on the Hill of legislation that would ban shark fin imports to the United States. And international action is likely, with several countries close to adopting new shark fishing restrictions in the next few weeks.

The book is called “Demon Fish: Travels Through the Hidden World of Sharks.” Out Tuesday.

Brief briefing

New State Department spokeswoman Victoria Nuland held an “on the record” briefing for reporters flying with Secretary of State Hillary Rodham Clinton on Wednesday en route to a meeting in Abu Dhabi with members of a coalition working to push Libyan dictator Moammar Gaddafi from power.

A promising start. Reporters always like on-the-record as opposed to the much overused background designation of “senior official.”

The only problem was that she uttered only about 200 words, beginning with: “Okay. So we are headed to Abu Dhabi for the third Contact Group meeting. As you know, these have been happening monthly. . .”

Then reporters heard from people who were “on background” and identified only as “senior government officials” named One, Two and Three. (No, not Larry, Moe and Curly.) We suspect they were State Department people but we weren’t on the plane.

So, according to a transcript, we read that “SENIOR GOVERNMENT OFFICIAL TWO” starts by telling us: “Okay. As [Senior Government Official One] said, this is the third meeting. . .”

Wait a minute! Isn’t that what Nuland just told us?

Back in the old days, Secretaries Colin Powell and Condoleezza Rice would brief the traveling press — on the record — before every stop.

It’s official

As expected, President Obama has tapped career Foreign Service officer Earl Anthony “Tony” Wayne, now deputy ambassador to Kabul, to be ambassador to Mexico. Wayne, whose diplomatic career started in 1975, served in a number of jobs in Europe and was assistant secretary of state for economic and business affairs for six years before becoming ambassador to Argentina in 2006.

Wayne’s first task probably will be to patch things up with Mexico’s President Felipe Calderon, whose relationship with former ambassador Carlos Pascual was, at best, rocky. Pascual, who’s now special envoy and coordinator for international energy affairs, resigned in March after WikiLeaks put out a cable in which he complained of incoherence in Mexico’s fight against drug cartels. Calderon was not happy.

Also, Obama has picked prominent conservationist Rebecca R. Wodder, who has been president and chief executive of American Rivers since 1995, to be assistant secretary of interior for fish and wildlife.

Cambridge bound

Looks like a chunk of the Obama National Economic Council staff is decamping to Harvard this fall. The departing group includes: Sarah Cannon, Bryan Jung and Kyle Watkins to Harvard Business School; and Pascal Noel, who is going for a doctorate in economics. Eric Lesser, who worked for departing Council of Economic Advisers chief Austan Goolsbee, is off to Harvard Law School.

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