John,
The airline industry is unfortunately under no obligation to provide any insurance for photographers, or anyone else. As a flyer, under the terms of agreement for accepting your airline ticket, you are the flyer agree to follow the airlines rules and regulations.
You, as a flyer, can choose to pack your gear in Pelican cases and check it, or find solutions to bring it on board. There are many creative solutions for carrying gear on board flights. For a year I flew approximately 15,000 miles per week with a Think Tank Airport Addicted backpack loaded around 60+lbs.
In the United States, the TSA specifically allows photographers to travel with 1+1+1, this is one full-size carry on, one full-size photographic carry on, one personal item. The problem with this TSA allowance is that the airlines are in no way required to accept or adhere to this allowance. in face some airlines specifically state in their standard operating procedures for gate agents that this rule not be accepted.
While airlines are not liable for any electronics you may check, this rules does NOT apply to 'valet' checked bag (bags left at the stairs of regional jets or turbo props). The problem here however is proving the gear was damaged by the airline and then suing the airline.
If you are interested in finding solutions to these issues, and other issues related to traveling as a photog, feel free to visit the blog I have maintained over the past two years to help photogs fly easier, smarter and with less stress at
http://www.flyingwithfish.com While I do not have the Federal Gov't experience like Don above, I study these topics in detail, and have often been quoted as an expert on many related topics by Popular Photographer, as well as having been featured on Good Morning America, recently sought out by CFO Magazine for my input on the business travel market, as well as quoted and referenced in a number of international newspapers. At this time I've even got a restructuring international airlines picking my brain.
Happy Flying
-Fish