Aurigny says two leased aircraft are undergoing maintenance following recent tech issues.
The two ATRs in question are G-PEMB and another which was 'wet leased' by Aurigny earlier this year, meaning its owner is responsible for maintenance.
G-PEMB arrived into Guernsey last month from the USA and underwent an initial check.
It was put into service on Friday, 9 August, but since then, what are described as 'expected teething issues' have grounded the aircraft while Aurigny engineers work to fix them.
The airline experienced delays yesterday due to heavy fog in Guernsey, and it warns there may be some impact today because of that, and the fact G-PEMB is not in service.
It is not known what the other ATR's owners are doing about maintenance checks.
Aurigny says passengers should check the flight disruption page on its website for updates.
G-PEMB is the fourth aircraft to joins Aurigny's fleet, but unlike its other ATRs, it is leased.
The airline will take possession of a fifth leased ATR in September.

Healthy heart initiative launches at Guernsey Library
Group to examine the complaints process of Guernsey's health service
Dornier aircraft lands in Guernsey for the final time
£130,000 needed to treat Guernsey toddler's brain injury
Channel Island pooches compete for Dog of the Year title
Guernsey homelessness charity supports more than 125 people in first year
Guernsey Pancake Day fundraiser cancelled
American descendants encouraged to visit Guernsey