Check the airline policy, I am willing to bet they have a base coverage, anything over that value you have to purchase additional coverage. It is usually pretty inexpensive in the long run. I ship bikes via Amtrak a fair bit, their base value is $250 IIRC. It costs ~$5 to bump that insurance up to $1,000. Well worth the cost IMHO. I suspect the airlines are the same way.
Aaron