Dublin Airport's been given six weeks to cut the number of night flights.
It follows complaints by residents near the facility.
Fingal County Council's issued an enforcement notice which found the number of nighttime flights currently operating at Dublin Airport amount to an ' unauthorised development'
It says the summer schedule which is being carried out is in breach of the limit applied as a planning condition.
Locals had complained that stressful and disturbing noise from planes was preventing people from sleeping.
daa now has six weeks to reduce the number of flights at night to an average of 65.
In a statement, the operators of the airport says it is disappointed at the decision to give 6 weeks notice to reduce the number of flights between 11 pm and 7 am.
It wants the local authority to suspend what it calls these 'overly onerous conditions'