Aer Lingus carried a record 1.1 million passengers last month as it boosted the number of services it operates to the US.
The airline's mainline traffic - which excludes services operated by Aer Lingus Regional - rose 5.6pc during the month.
On services to North America, which are almost entirely accounted for by routes to the United States, Aer Lingus carried 168,000 passengers, 18.3pc more than it did in July last year.
Its short-haul services to the UK and Europe carried 962,000 passengers, which was 3.7pc more than in July 2014.
The load factor at Aer Lingus last month, or the percentage of available seats it filled, was 88.6pc. That was 1.3 percentage points higher year-on-year.
The load factor on transatlantic services dipped 0.5 percentage points to 90.3pc, but that came as Aer Lingus added almost 21pc more capacity on those routes in July compared to July 2014.
Aer Lingus is poised to be acquired by British Airways owner IAG in coming weeks.
Ryanair is due to formally accept the €1.36bn takeover offer by August 18 - the final deadline for agreeing to sell Aer Lingus shares to IAG.
That means that the takeover should be completed by early September. IAG chief executive Willie Walsh has said he'll provide more detail about his plans for Aer Lingus at an investor day in November.
He intends to use Aer Lingus to grow IAG's transatlantic services. New routes that are likely to go ahead include Dublin-Los Angeles, and another service to the US east coast.
Announcing first half results last week, Aer Lingus chief executive Stephen Kavanagh said that Miami is one city that may be of interest to the airline.
He also said that Aer Lingus could capture more traffic to Orlando.
Aer Lingus has been using smaller Boeing 757 aircraft on some services to North America that might not otherwise be profitable using larger aircraft. It's also beefing up its presence over the winter to Chicago.
The airline will also have to contend with an impending fares war with Ryanair out of Dublin this winter, a challenge Mr Kavanagh has said Aer Lingus is "absolutely" up to meeting.
The number of passengers carried by Aer Lingus Regional fell 5.6pc in July to 134,000. The service is operated on a franchise basis by Stobart Air.
Aer Lingus has successfully used the model to attract large numbers of passengers from the UK who use Dublin for onward travel to the US.
Meanwhile, IAG said yesterday that it will buy $4.7bn (€4.2bn) worth of Airbus jets to help Iberia, which it owns, to expand and replace its existing long-haul fleet.
IAG has converted eight A350 and three A330 options into firm orders. They'll be delivered between 2016 and 2021.
It has also converted 20 options to buy Airbus 320neo aircraft into firm orders.
Those aircraft will be delivered between 2020 and 2021. IAG said the neo jets can be used "by any airline in the group", which will include Aer Lingus, for fleet replacement.