It’s official: Aer Lingus will leave the oneworld alliance as of Apr. 1, 2007. Members of other oneworld frequent flyer programs may book award flights on Aer Lingus through Mar. 31, 2007, and all award travel booked by that date will be honored, regardless of the date flown. Similarly, members will earn miles and tier-status points and have use of Aer Lingus lounges through Mar. 31, 2007. Aer Lingus will continue to participate in the Global Explorer round-the-world fare after the airline withdraws from oneworld. Four other oneworld partners serve Ireland: American Airlines, British Airways, Finnair, and Iberia.