BBC News - By Katy Austin, Becky Morton & Lora Jones
Mr O'Toole said the speed the travel industry had recovered had taken Manchester Airport by surprise, leaving it short-staffed.
He added that 220 new staff had been recruited, who were currently being trained and would start work over the coming weeks.
In the meantime, he urged travellers to be prepared for longer waits and to arrive three hours in advance to ensure they do not miss their flights around the Easter holidays.
While Manchester Airport appears to be the worst affected, Heathrow, Gatwick and Birmingham have also been hit by delays and cancellations.