Free parking will be offered for compassionate and inter-island travel, hospital appointments and blue badge holders, Highlands and Islands Airport Limited (Hial) announced.
The free drop-off and pick-up period will also be extended from one to two hours when the parking fees are introduced on 1 July.
Shetland MSP Tavish Scott has called for Scottish Government-controlled Hial's board to be dismissed if it does did not scrap the charging plans.
Hial said the moves followed consultation on the charges, announced in March, and a survey of 549 airport users.
“Clearly, if given a preference, most people would not wish to pay for a service that had previously been provided for free.
"However, there remains an urgent need to raise the revenue required to reinvest in maintaining viable air services for our island communities.
"We believe a fair and proportionate parking charge for airport users is one means of maintaining the necessary investment.
"The money raised will be continuously reinvested to maintain and ultimately improve facilities, ensuring the long-term resilience of airport operations on the islands.”
The survey found one in four people who parked at the airports might change how they travelled there, such as being dropped off or taking the bus.
Inverness and Dundee airports already have parking charges.