JetBlue and Aer Lingus today revealed details of an alliance between the two carriers, ending several months of speculation since the airlines first confirmed a deal may be in the works. On April 3, the airlines will roll out the ability for customers to book connecting tickets on some of each other's flights. JetBlue customers will be able to fly to the airline's hub at New York JFK and then connect on an Aer Lingus flight to Ireland –- all on a single ticket. Aer Lingus customers will be able to fly to New York and then connect to many of JetBlue's U.S. destinations, also on a single ticket. As for the delay between the first rumblings of the deal and today's announcement, JetBlue spokesman tells BusinessWeek that "we were in negotiations for quite some time. These things take time."

The Wall Street Journal (subscription required) writes the pact is a "strategic partnership aimed at boosting traffic" but says it could also "test the limits of their bare-bones business models." The Journal adds "the alliance is unusual because budget airlines generally shun cooperation with other carriers. Traditional airlines routinely use such tie-ups to increase the number of destinations they can offer and thereby appeal to more travelers. But interweaving airlines' networks and sharing ticket revenue through what airlines call 'code sharing' is complex and can be expensive to manage."

Despite that, JetBlue and Aer Lingus say they can avoid those pitfalls because their pact will rely on connecting the booking capabilities of their websites. Enda Corneille, corporate-affairs director at Aer Lingus, tells the Journal the two airlines will not create a new class of fares, but rather just use the airlines' two booking engines to simply combine the cost of the connecting flights, flights that otherwise would have to be booked separately. "This is totally new," JetBlue CEO Dave Barger says to the Journal "It's electronically linking two carriers." If successful, Barger says he hopes to partner with other overseas carriers.