Does anyone know if a fee is charged if you pick up a car at Kona Airport and drop off the car at Hilo Airport?

Depends on the rental agency.
BTW, I got a notice from Hotwire yesterday about compact cars out of KOA for $12.95/day.

why not just ask them instead of posting here. they re the ones who would know.....

Thank you Shar for your "helpful" response

hbo6, Shar WAS being helpful. Instead of waiting to see if someone on Fodor's might answer your question, you would have already known the answer if you'd contacted the car rental agency.

thank you bettyk......why wait for someone on this forum to answer you when they COULD be wrong. the rental company would have the exact answer. I really ws trying to be helpful.

A couple of the rental companies do not charge, I think Budget and Dollar.

I usually try my dates on Orbitz for estimates, and then make reservations through the site directly, or through the Costco site (which allows an additional driver at no charge.)

I've had the best results with carrentals.com; just be sure to NOT prepay for any rental unless you have a killer deal; prices can vary quite a bit, the closer you get to your stay.
Drop off fees can vary from $0 to as much as $85. Depends, again, on the agency.

The drop charge on the BI is something to consider. I have found the best rate using:
discounthawaiicarrental.com for all 3 of the islands we will visit this winter.
For Maui and Kauai the agency that Discounthawaiicarrental.com found was Thrifty.
But ... for the BI the best rate was with AVIS because they did not have an extra "drop" charge for picking up at Kona and dropping at Hilo.
Hope this helps.
For Maui and Kauai the rate for an Economy 1 week rental is: $210.00 total.
For the BI it is: $199. for a 5 day rental of a COMPACT.
Check it out.
If anyone has a better deal for any or all of these islands, I would be interested as my reservation is not final.

My advice is to keep checking all sites; then, a final check on hotwire close to the date. The rates you have mentioned are ridiculous! (Unless you are renting over the holidays?)

Part of the reason for posting a Q is to gain additional info that Fodorites might have, non?

In any event - some good starting points provided and hopefully checking these out - and the various car rental agencies will point you to the best deal.

Not sure about Hawaii - but I always use www.carrentals.com here in the States/San Diego - and they provide a good list.

I think hbo6 has gone on to greener pastures.