Flybe has chopped several flights this summer and reduced its schedule on other routes.
Flights that have been cancelled are from Belfast City to Aberdeen, Inverness and Newcastle and from Birmingham to Aberdeen.
Flights operating at reduced frequency are from Belfast City to Birmingham, Edinburgh, Glasgow, Manchester and Southampton, and from Birmingham to Edinburgh and Glasgow.
The airline said the cancellations will apply from 28 July to 29 October.
It blamed late aircraft deliveries.