Limits are in place dur to staff sickness in air traffic control.
Ryanair's boss says his airline will not be cancelling any flights from Gatwick - despite limits being introduced because of staff sickness in air traffic control.
Mullingar's Michael O'Leary wants the chief executive of the operator Nats to resign - claiming arranging standby cover is the "most basic requirement."
164 cancellations will be shared between airlines until Sunday, to avoid delays and last-minute changes.
Nats insists its working closely with Gatwick.