American Airlines and JetBlue Airways launched their partnership yesterday, providing travelers with simplified bookings on connections with each carrier. Passengers on American can book connections on JetBlue from New York's JFK International Airport or Boston's Logan Airport to 18 domestic cities not previously served by American. JetBlue passengers, meanwhile, can now book connections to 14 international destinations served by American from those same airports. Customers can arrange the inter-carrier service on non-overlapping market routes through global distribution systems, travel agencies, AA ticket counters and AA Reservations. Soon, the airlines will offer joint frequent-flyer benefits, allowing customers to earn miles for one program on the other airline's flights.