Well, we saw this one coming with the US merger, but wow that was fast! Interline agreements end effective today and reciprocal frequent flier accrual will end April 1st. From the PR:
Beginning today, each airline will no longer accept new interline sales for travel on the other carrier. Effective April 1, customers will no longer earn miles or points when traveling on eligible routes operated by the other airline. All American AAdvantage miles or JetBlue TrueBlue points already accrued through this partnership will be credited to customers’ accounts and are not affected. The two airlines are working together to ensure these changes have little impact to customers.