Yes a 6th Aircraft is need some days.
Here is a Sunday morning...
EZY6755 Malaga 06:00 A319
EZY6701 Alicante 06:10 A320
EZY6793 Faro 06:25 A319
EZY6783 Krakow 07:00 A319
EZY6707 Dubrovnik 07:05 A320
EZY6671 Barcelona 07:50 A320
Few other days need 6 six aircraft.