Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Londonderry to Belfast City Airport as you normally would.
For a flight from Londonderry to Belfast City, you will be flying from Eglinton. Londonderry Eglinton (LDY) is just 6.7 mi from the center of the city. Eglinton is the only Londonderry airport and it handles 0 outbound flights to Belfast City per day. 0 airlines have flights to Belfast City from Londonderry Eglinton on a regular basis.