I'd say doable but tight. An hour delay would leave you with 45 minutes to pass immigration and run over to the schengen gates and board.
Note that the AA PHL-ATH is on time 69% of the time with a 46 minute average delay. Based on averages this would leave you an hour.
The advice would be to OLCI the A3 flight and have your boarding pass available (printed or phone) to avoid any loss of time. Of course if your AA flight goes tech or is delayed by more than an hour you will most likely be out of luck.
Thank you GVA.
I actually noticed when booking the ATH - JTR that it departs at 10:10am not 10:55 as I thought. The next departing flight is at 11:55am.
My idea is to book a flex fare for the 10:10am and 11:55am.
If I had great luck and made the 10:10am then cancel the 11:55am.
However, if I miss the 10:10am does a flex fare allow for me to cancel after departure? It's been hard to find this information. I believe I did see a cancellation fee, but can't discern if refund is possible after departure.
-Andrew