Rooster is managing proactive consumer and trade PR, in addition to acting as a press office for cheapflights.co.uk and its sister sites, cheapholidaydeals.co.uk and cheapaccommodation.com.
Liz Faherty, director of business development at Cheapflights, said initial discussions had been held with eight agencies for the contract.
Rooster won a final four-way shootout against the incumbent, KBC PR and Rare Communications.