Am I assuming 2 seats in Coach?
Here's what I found,
Sun, 4/10 LH411, JFK-MUC 17:35-8:05+1
Mon, 4/11 LH688, MUC-TLV, 9:25-13:55
Wed, 4/27 A3929, TLV-ATH, 7:00-9:00
Wed, 4/27 LH1279, ATH-FRA, 13:30-15:30
Wed, 4/27 LH404, FRA-JFK, 17:00-19:40
Could possibly find a better return but thats what I found for 2 seats at the moment.
In general your best bet is calling USAirways and trying to find a nice agent to look for flights for you.
Or just post here
Partner flights have to be booked over the phone.