There are three local firms in Kalyves/Almirida area who operate from the airport.
Kalives Travel: 0030 28250 31046; 0030 6973 70490; http://www.kalivestravel.gr/
; Fax: +0030 28250 31022; Contact form on the web site. (Georgios and Evyenia)
Auto-Club Rentals: 0030 28250 32382; 0030 6974 774 201; http://www.autoclub-rentals.gr/
Flisvos Car Rental: 0030 28250 31337; 0030 6972 779 777; http://www.flisvos.com/
; Contact form on website. (Manolis).
If you want to contact them by phone out of season you may need to try the mobile numbers (beginning 697)
Over the years I've used all of them and they've all been reliable and cheaper than booking from the UK using the big rental sites. On average I've found Flisvos to be slightly more expensive than the other two and all three are much of a muchness for service. They all supply cars from Xania airport.
A couple of months ago I rented a vehicle to give a thorough road test to the type we were considering buying. Flisvos was the only one with that type available at the time and the cost was reasonable. Now waiting supply of the new car and have rented from AutoClub on very
good (winter) terms for a 60 days period.