Ryanair will be launching more new routes for Summer 2017 in September according to NI Travel News!
Even better news for Northern Ireland travellers and Belfast International Airport is that the Ryanair growth will continue, with or without local government support, and the airline intends to announce more new routes (to start in summer 2017) in September.
Up to 40 New Routes Could Come to Belfast - Ryanair
Edit- Still only 2 based aircraft are needed still for Winter 2016/17... I'm guessing they will be back soon to announces routes for the 3rd aircraft. As they are saying that it will be 3 based aircraft for winter 2016/17..