Social media users posted pictures of the airline CEO assisting passengers on another busy day at terminal one on Saturday.
It was another busy weekend at the airport which is continuing to recruit additional security personnel in the midst of the busy summer season.
Last month Daa was forced to apologise after thousands of customers queued for hours outside the terminal building, with many passengers ultimately missing their flights.
Daa said passengers who missed holidays on foot of the security queue delays may be able to get the cost of their break back. Around 1,500 passengers missed their flights.
"All relevant, direct, and reasonably incurred costs that are vouched or substantiated by receipts or evidence will be reviewed on a case-by-case basis,” a Daa spokesperson told the Sunday Independent.
Following the scandal, Daa announced it would re-assign additional staff to security checkpoints while recruitment continues.
The Authority said over 600 taskforce members have worked more than 3,000 shifts over the past 10 weeks, “ to support our phenomenal wider security team, as we continue to welcome passengers back to Dublin Airport and rebuild our business after the pandemic”.
Over 800 Dublin Airport employees, including a large number of security personnel, left the organisation by the end 2020 through a voluntary redundancy scheme.
Daa is still advising passengers to arrive at the airport two and a half hours before short-haul flights and three and a half hours before long-haul flights, while an extra hour should be given if bags need to be dropped or if people need to visit a check-in desk.
Mr O’Leary’s appearance on the front line with Dublin Airport and Ryanair staff over the weekend comes as bookings for Europe's biggest budget airline have continued to strengthen.
Mr O'Leary told Reuters that "we've seen very strong bookings through May. We had 92pc load factor in May. We think that would rise to about 94pc in June. And July, August, and September look very strong with higher load factors and also higher fares".
"Fares will be up probably high single digits 7,8, 9 percent over summer 2019," he said.
French cabin crew at Ryanair went on strike last week demanding better pay and working conditions, leading more than 40 flights being cancelled.
Meanwhile, Ryanair cabin staff in Portugal and Italy plan to strike in late June.
SNPVAC, Portugal's union of civil aviation personnel, said workers would walk out on June 24, 25 and 26, demanding better working conditions.
"This mobilisation is not only an opportunity to put the spotlight on multiple attacks on workers' dignity and to make this reality known but also a moment to show unity and solidarity against dumping", the union said.
Meanwhile, in Italy, the FILT-CGIL and UIL Trasporti unions said Ryanair staff and crew have called a 24-hour strike for June 25, seeking improved pay and conditions.
The news follows an announcement by unions representing some of Ryanair’s cabin staff in Spain that they plan to strike from June 24-26 and June 30 to July 2, following pay disputes.