The Dublin-based BBDO network agency, Irish International, is the incumbent on both accounts.
In the UK, the creative account had been run through Abbott Mead Vickers BBDO, while PHD looked after media. However the brand has been largely inactive in the UK for several months.
In 2000, AMV broadened its personality-led advertising in a bid to convince business fliers that they can save time by flying with Aer Lingus.
One poster showed Roy Keane, the Manchester United and Republic of Ireland footballer renowned for his hard tackling, with the line: "Late ... me ... never."
The review, which covers all of Aer Lingus's Irish and international activity, is being led out of the airline's offices in Dublin.
Aer Lingus has just returned to profitability following two years of losses, which have been compounded by the rise of the budget airline Ryanair.
Aer Lingus relies greatly on transatlantic passengers who, even before 11 September, had been scared off by the outbreak of foot-and-mouth disease.
However, despite its return into the black, the airline has ruled out any early plans for privatisation.