Aer Lingus said it saw a significant increase in the number of lost luggage items attributable to the security alert at Heathrow Airport.
300 items of luggage went missing on flights between Dublin, Cork and Shannon airports and Heathrow on Sunday while a similar number was lost on Monday.
On a typical Sunday, Aer Lingus said it could have 50 reports of missing luggage.
This afternoon, it said most of the missing baggage from Air Lingus flights from Heathrow have now been returned to their owners. It added that the situation concerning baggage has returned to normal.
Aer Lingus operates 22 return flights between Ireland and Heathrow Airport daily.
Earlier, British Airways said it was trying to reunite some 5,000 items of lost luggage with passengers since the security alert last week.
