UPDATE, 6/21/12, 3:15 p.m. EDT: A&L Goodbody corporate partners John Given and Alan Casey are advising Ryanair in connection with its bid for Aer Lingus.

European budget airline Ryanair Holdings said Tuesday that it has made another offer to buy the roughly 70 percent of rival Irish carrier Aer Lingus Group that it does not already own.

With any potential deal involving the competing airlines likely to face intense scrutiny from regulators, Aer Lingus has turned to its longtime antitrust counsel, Alec Burnside of Cadwalader, Wickersham & Taft, to advise it on the matter, while Cleary Gottlieb Steen & Hamilton is advising Ryanair on European Union competition aspects of the bid.

Ryanair, which has a 29.8 percent stake in the Irish airline, is offering $1.64 in cash for each Aer Lingus share—a premium of 38 percent over the target’s Tuesday closing price. Aer Lingus is objecting to the latest Ryanair offer, issuing a statement on Wednesday saying that the $883 million price tag undervalues the company.

Ryanair offered $1.88 billion to buy its rival in 2006, but in a first in the European airline industry, saw the deal scuttled by the Irish government (which owns another 25 percent stake in publicly traded Aer Lingus), regulators, and Aer Lingus employees (Ryanair did, however, pick up its minority stake. The European Commission then blocked a 2008 attempt by Ryanair to acquire the remainder of Aer Lingus for $948 million on the grounds that a full merger of the two Dublin-based airlines would ensure Ryanair a monopoly on flights out of the Irish capital. In 2010 a European Union appeals court affirmed that decision, but denied Aer Lingus’s attempt to force Ryanair to sell its minority stake, according to our prior reporting.

Cadwalader’s Burnside, based in Brussels, joined the firm from Linklaters last year and has represented Aer Lingus in its various efforts to fend off Ryanair’s advances since the initial takeover bid.

Cleary’s team advising Ryanair on the bid’s E.U. antitrust aspects is led by Nicholas Levy, a partner in the firm’s Brussels and London offices.

(In the past, Ryanair has turned to Irish firm A&L Goodbody as outside counsel on transactions, including its initial bid for Aer Lingus and subsequent hostile takeover attempt. A spokesman at A&L did not respond to a request for comment.)

While the failure of Ryanair’s previous attempts to take over Aer Lingus has not prevented the company from continuing to try to acquire its five, the latest bid comes amid increased regulatory scrutiny of the Aer Lingus stake that Ryanair already owns. Saying that a complete takeover by Ryanair could result in higher prices for Aer Lingus customers, Britain’s Office of Fair Trading last week requested that U.K. antitrust watchdog the Competition Commission conduct a full probe of Ryanair’s Aer Lingus holdings, according to the Irish Times. The regulator, which could force Ryanair to sell its current stake, is expected to rule on the matter by November 29.

That probe notwithstanding, Ryanair believes that industry data supports its move to acquire its rival. Ryanair argues in its announcement of the offer that passenger traffic at Dublin Airport fell 20 percent between 2007 and 2011, affording competitors the opportunity to break into that market. Ryanair also contends that, with acquisitions by other European carriers such as Air France and British Airways consolidating the continent’s market, Aer Lingus’s best interests could be secured in a tie-up. Ryanair CEO Michael O’Leary promises that Aer Lingus will see its traffic increase from the current 9.5 million annual passengers to 14 million in the next five years should the acquisition move forward.