The US and Croatia began a four-day long air force exercise. US F-16s and Croat Mig-21s engaged in exercises over Istria (along the Adriatic). The AP reported that the US and Croat pilots will trade-off and fly one anothers aircraft during the exercise. This will, of course, give Croat pilots greater familiarity with NATO equipment, which Croatia intends to acquire as part of its upgrade program. RFE has reported recently that Croatia will be asked to join NATOs Membership Action Plan (a prep plan for would-be NATO members). Training exercises (such as this one) would be part of that program.