Tobagoman:
I went through security on the Big Island last month and it was pretty quick, except for the double screening of carry-ons. We got there less than two hours before our flight out and still sat around and waited at the terminal, and this was right after the earthquake with everyone trying to get out on the first few flights to be allowed in and out of the island.
So 3 hours would be massive overkill. Good luck and enjoy!
Ditto on the double screening of carry-ons. You would think at an airport with as many scuba divers as they would get, that their TSA personnel would recognize a reg/gauge/computer setup. WRONG!!!
At that time I was carrying these in my carry-on, to prevent damage and/or theft. The TSA screener saw something "suspicious" on the x-ray screen. I told her it was scuba gear, and she verified that it was after searching it.
The part I don't get is after she searched the bag (including the pockets)
she put it back through the x-ray machine again!. It's already been x-rayed once, and thoroughly hand searched, why is it being x-rayed again?
As far as the 3 hour lead time, you can never be too safe. At busy airports such as Honolulu, you can never guarantee that there is not a long line at either check-in or the security screening point. Trust me, I barely made my Auckland-Sydney flight a couple of weeks ago despite arriving 2 1/2 hours ahead of time.
That extra hour or two will be downright cheap compared to the cost of missing your flight, and having to rebook it (at much higher prices, unless you flew First Class, Business, or Full-Fare Coach) as well as any possible overnight hotel stays if you missed the last flight to your destination for that day. BTDT.