It might be possible for both you and your wife to gain a significant amount of miles (40,000--50,000) fairly quickly through credit card offers connected to major carriers such as AA, DL or UA. If you have some miles in one or more of these programs to begin with, you might be able to increase your balances to the 60,000 normally needed for a RT trip to Europe. In addition, AA offers such trips for 40,000 in the off-season, which includes some Fall travel.