But Flybe and Aurigny have now vowed to review their charges.
The Times has quoted that the cost of handling an average transaction is about 0.6%.
But Flybe, which includes franchise partner Blue Islands, charges 3% on all cards, with a minimum charge of £5, while States-owned airline Aurigny charges 2.5%, with a minimum charge of £2.
Flybe has now announced it will reduce its charges and scrap the minimum fee, but has not said when this will take place and what the new level will be.
Aurigny said it offered the lowest credit card fees of any airline operating in Guernsey.
