From the TSA site:
Tackle Equipment - Fishing equipment should be placed in your checked baggage. Some tackle equipment can be considered sharp and dangerous. Expensive reels or fragile tackle such as fly's should be packed in your carry-on baggage.
http://www.tsa.gov/travelers/airtrav...rial_1188.shtm
However, here are some comments from a similar thread on Dan Blanton's board:
"I lost a box of San Juan river flies (size 20-26) at Albuquerque airport because: 'TSA has determined that fish hooks are weapons'.
As others have posted, TSA can do whatever they want to, and there is no arguing with them once some agent has made up their mind."
Size 20-26 flies are TINY. Here's another comment:
"I decided to call TSA's 800 number to confirm. I spoke to a representative. She was not a flyfisher. She told me -- I am not making this up -- that you could carry on flies as long as you didn't include the hooks."
http://www.danblanton.com/viewarchiv...arch200609.php