Colonel Ivan Petrenko, the Chief of Aviation of Ukraine's "East" Air Force Command is one of the two pilots who lost his life in the crash of Sukhoi Su-27UB fighter in Vinnytsia region.
"This is a sad day for the United States and Ukraine", Maj.
Military authorities said the bodies of the two airmen had been recovered.
The name of the American pilot is being withheld pending next of kin notification, Bowyer-Meeder said. A Ukrainian pilot was also killed in the incident. The command said it "can confirm a US service member was involved in this incident", but stopped short of confirming the American's death.
The U.S. and Ukrainian governments are conducting an investigation to determine the cause of the accident.
"We have seen reports claiming a USA casualty and can confirm a USA service member was involved in this incident", said a USAFE spokesperson.
The Ukrainian military said participants in the Clear Sky maneuvers held a ceremony at a nearby airfield to commemorate the airmen killed in the incident.
Clear Sky 2018 is a joint and multi-national exercise that involves approximately 950 people from Belgium, Denmark, Estonia, the Netherlands, Poland, Romania, Ukraine, the United Kingdom and the United States, the Air Force said.
US assets participating include six F-15C Eagles from the 144th Fighter Wing, based at Fresno Air National Guard Base, Calif.; an F-15D from the 48th Fighter Wing, at RAF Lakenheath, England; and C-130Js from the Guard's 146th Airlift Wing, operating out of Vinnytsia Air Base. The goals of the exercise were to enhance regional security and cooperation between Ukraine and North Atlantic Treaty Organisation allies, and other partners in the region.
Garrison extended "our deepest condolences" to the family, friends and fellow airmen of both the USA airman and Ukrainian aviator killed in the crash.
California units were heavily represented in Clear Sky with F-15C Eagles and C-130J Super Hercules.