Wizzair
Wizzair Cork-Katowice service to increase to 5 weekly from mid June to mid September, with flights every day bar Tuesdays and Thursdays. Obviously they're benefiting from the withdrawal of Cork-Krakow by Centralwings. Also had a look at the fares. Very hard to find any flights less than €100 each way over the peak summer months so yield must be okay.
Cork-Gdansk meanwhile will operate 3 weekly over the summer.