Forever hopeful, I kept my travel plans to Lisbon for July, and figured if necessary, I would cancel as time got closer to departure. I just checked my flight details on the AA website, and saw that the connecting flight from DFW to PHL was not canceled, but the flight from PHL to LIS was gone. Based on this, I am assuming AA is not planning on resuming flights to many parts of Europe this summer. If you are holding a reservation to go abroad, keep an eye on it. I was not given any notification of the cancellation from American.
Footnote: On 4/7 I was able to speak with an AA representative (without any wait), and was informed there will be no flights all summer to Lisbon on AA. I imagine that will be true for other cities as well.