My wife has filed for Adjustment of Status. Can she travel outside the U.S. while she is waiting for her interview?

Unless your wife is in H-1B or L-1 status, she cannot travel outside the U.S. while the Adjustment of Status is pending without permission from USCIS. If she does, USCIS will presume that she has elected to process her green card at a U.S. Consulate and will deny the Adjustment of Status and send the case to the National Visa Center. If she first obtains Advance Parole from USCIS, she can travel outside the U.S. and then re-enter for the purpose of completing the Adjustment of Status.